api, login, auth

55 files changed, 5237 insertions, 0 deletions

diff --git a/node_modules/mongodb/lib/operations/add_user.js b/node_modules/mongodb/lib/operations/add_user.js
new file mode 100644
index 0000000..9c02510
--- /dev/null
+++ b/node_modules/mongodb/lib/operations/add_user.js
@@ -0,0 +1,98 @@
+'use strict';
+
+const Aspect = require('./operation').Aspect;
+const CommandOperation = require('./command');
+const defineAspects = require('./operation').defineAspects;
+const crypto = require('crypto');
+const handleCallback = require('../utils').handleCallback;
+const toError = require('../utils').toError;
+
+class AddUserOperation extends CommandOperation {
+  constructor(db, username, password, options) {
+    super(db, options);
+
+    this.username = username;
+    this.password = password;
+  }
+
+  _buildCommand() {
+    const db = this.db;
+    const username = this.username;
+    const password = this.password;
+    const options = this.options;
+
+    // Get additional values
+    let roles = [];
+    if (Array.isArray(options.roles)) roles = options.roles;
+    if (typeof options.roles === 'string') roles = [options.roles];
+
+    // If not roles defined print deprecated message
+    // TODO: handle deprecation properly
+    if (roles.length === 0) {
+      console.log('Creating a user without roles is deprecated in MongoDB >= 2.6');
+    }
+
+    // Check the db name and add roles if needed
+    if (
+      (db.databaseName.toLowerCase() === 'admin' || options.dbName === 'admin') &&
+      !Array.isArray(options.roles)
+    ) {
+      roles = ['root'];
+    } else if (!Array.isArray(options.roles)) {
+      roles = ['dbOwner'];
+    }
+
+    const digestPassword = db.s.topology.lastIsMaster().maxWireVersion >= 7;
+
+    let userPassword = password;
+
+    if (!digestPassword) {
+      // Use node md5 generator
+      const md5 = crypto.createHash('md5');
+      // Generate keys used for authentication
+      md5.update(username + ':mongo:' + password);
+      userPassword = md5.digest('hex');
+    }
+
+    // Build the command to execute
+    const command = {
+      createUser: username,
+      customData: options.customData || {},
+      roles: roles,
+      digestPassword
+    };
+
+    // No password
+    if (typeof password === 'string') {
+      command.pwd = userPassword;
+    }
+
+    return command;
+  }
+
+  execute(callback) {
+    const options = this.options;
+
+    // Error out if digestPassword set
+    if (options.digestPassword != null) {
+      return callback(
+        toError(
+          "The digestPassword option is not supported via add_user. Please use db.command('createUser', ...) instead for this option."
+        )
+      );
+    }
+
+    // Attempt to execute auth command
+    super.execute((err, r) => {
+      if (!err) {
+        return handleCallback(callback, err, r);
+      }
+
+      return handleCallback(callback, err, null);
+    });
+  }
+}
+
+defineAspects(AddUserOperation, Aspect.WRITE_OPERATION);
+
+module.exports = AddUserOperation;
diff --git a/node_modules/mongodb/lib/operations/admin_ops.js b/node_modules/mongodb/lib/operations/admin_ops.js
new file mode 100644
index 0000000..d5f3516
--- /dev/null
+++ b/node_modules/mongodb/lib/operations/admin_ops.js
@@ -0,0 +1,62 @@
+'use strict';
+
+const executeCommand = require('./db_ops').executeCommand;
+const executeDbAdminCommand = require('./db_ops').executeDbAdminCommand;
+
+/**
+ * Get ReplicaSet status
+ *
+ * @param {Admin} a collection instance.
+ * @param {Object} [options] Optional settings. See Admin.prototype.replSetGetStatus for a list of options.
+ * @param {Admin~resultCallback} [callback] The command result callback.
+ */
+function replSetGetStatus(admin, options, callback) {
+  executeDbAdminCommand(admin.s.db, { replSetGetStatus: 1 }, options, callback);
+}
+
+/**
+ * Retrieve this db's server status.
+ *
+ * @param {Admin} a collection instance.
+ * @param {Object} [options] Optional settings. See Admin.prototype.serverStatus for a list of options.
+ * @param {Admin~resultCallback} [callback] The command result callback
+ */
+function serverStatus(admin, options, callback) {
+  executeDbAdminCommand(admin.s.db, { serverStatus: 1 }, options, callback);
+}
+
+/**
+ * Validate an existing collection
+ *
+ * @param {Admin} a collection instance.
+ * @param {string} collectionName The name of the collection to validate.
+ * @param {Object} [options] Optional settings. See Admin.prototype.validateCollection for a list of options.
+ * @param {Admin~resultCallback} [callback] The command result callback.
+ */
+function validateCollection(admin, collectionName, options, callback) {
+  const command = { validate: collectionName };
+  const keys = Object.keys(options);
+
+  // Decorate command with extra options
+  for (let i = 0; i < keys.length; i++) {
+    if (Object.prototype.hasOwnProperty.call(options, keys[i]) && keys[i] !== 'session') {
+      command[keys[i]] = options[keys[i]];
+    }
+  }
+
+  executeCommand(admin.s.db, command, options, (err, doc) => {
+    if (err != null) return callback(err, null);
+
+    if (doc.ok === 0) return callback(new Error('Error with validate command'), null);
+    if (doc.result != null && doc.result.constructor !== String)
+      return callback(new Error('Error with validation data'), null);
+    if (doc.result != null && doc.result.match(/exception|corrupt/) != null)
+      return callback(new Error('Error: invalid collection ' + collectionName), null);
+    if (doc.valid != null && !doc.valid)
+      return callback(new Error('Error: invalid collection ' + collectionName), null);
+
+    return callback(null, doc);
+  });
+}
+
+module.exports = { replSetGetStatus, serverStatus, validateCollection };
diff --git a/node_modules/mongodb/lib/operations/aggregate.js b/node_modules/mongodb/lib/operations/aggregate.js
new file mode 100644
index 0000000..e0f2da8
--- /dev/null
+++ b/node_modules/mongodb/lib/operations/aggregate.js
@@ -0,0 +1,106 @@
+'use strict';
+
+const CommandOperationV2 = require('./command_v2');
+const MongoError = require('../core').MongoError;
+const maxWireVersion = require('../core/utils').maxWireVersion;
+const ReadPreference = require('../core').ReadPreference;
+const Aspect = require('./operation').Aspect;
+const defineAspects = require('./operation').defineAspects;
+
+const DB_AGGREGATE_COLLECTION = 1;
+const MIN_WIRE_VERSION_$OUT_READ_CONCERN_SUPPORT = 8;
+
+class AggregateOperation extends CommandOperationV2 {
+  constructor(parent, pipeline, options) {
+    super(parent, options, { fullResponse: true });
+
+    this.target =
+      parent.s.namespace && parent.s.namespace.collection
+        ? parent.s.namespace.collection
+        : DB_AGGREGATE_COLLECTION;
+
+    this.pipeline = pipeline;
+
+    // determine if we have a write stage, override read preference if so
+    this.hasWriteStage = false;
+    if (typeof options.out === 'string') {
+      this.pipeline = this.pipeline.concat({ $out: options.out });
+      this.hasWriteStage = true;
+    } else if (pipeline.length > 0) {
+      const finalStage = pipeline[pipeline.length - 1];
+      if (finalStage.$out || finalStage.$merge) {
+        this.hasWriteStage = true;
+      }
+    }
+
+    if (this.hasWriteStage) {
+      this.readPreference = ReadPreference.primary;
+    }
+
+    if (options.explain && (this.readConcern || this.writeConcern)) {
+      throw new MongoError(
+        '"explain" cannot be used on an aggregate call with readConcern/writeConcern'
+      );
+    }
+
+    if (options.cursor != null && typeof options.cursor !== 'object') {
+      throw new MongoError('cursor options must be an object');
+    }
+  }
+
+  get canRetryRead() {
+    return !this.hasWriteStage;
+  }
+
+  addToPipeline(stage) {
+    this.pipeline.push(stage);
+  }
+
+  execute(server, callback) {
+    const options = this.options;
+    const serverWireVersion = maxWireVersion(server);
+    const command = { aggregate: this.target, pipeline: this.pipeline };
+
+    if (this.hasWriteStage && serverWireVersion < MIN_WIRE_VERSION_$OUT_READ_CONCERN_SUPPORT) {
+      this.readConcern = null;
+    }
+
+    if (serverWireVersion >= 5) {
+      if (this.hasWriteStage && this.writeConcern) {
+        Object.assign(command, { writeConcern: this.writeConcern });
+      }
+    }
+
+    if (options.bypassDocumentValidation === true) {
+      command.bypassDocumentValidation = options.bypassDocumentValidation;
+    }
+
+    if (typeof options.allowDiskUse === 'boolean') {
+      command.allowDiskUse = options.allowDiskUse;
+    }
+
+    if (options.hint) {
+      command.hint = options.hint;
+    }
+
+    if (options.explain) {
+      options.full = false;
+      command.explain = options.explain;
+    }
+
+    command.cursor = options.cursor || {};
+    if (options.batchSize && !this.hasWriteStage) {
+      command.cursor.batchSize = options.batchSize;
+    }
+
+    super.executeCommand(server, command, callback);
+  }
+}
+
+defineAspects(AggregateOperation, [
+  Aspect.READ_OPERATION,
+  Aspect.RETRYABLE,
+  Aspect.EXECUTE_WITH_SELECTION
+]);
+
+module.exports = AggregateOperation;
diff --git a/node_modules/mongodb/lib/operations/bulk_write.js b/node_modules/mongodb/lib/operations/bulk_write.js
new file mode 100644
index 0000000..8f14f02
--- /dev/null
+++ b/node_modules/mongodb/lib/operations/bulk_write.js
@@ -0,0 +1,104 @@
+'use strict';
+
+const applyRetryableWrites = require('../utils').applyRetryableWrites;
+const applyWriteConcern = require('../utils').applyWriteConcern;
+const MongoError = require('../core').MongoError;
+const OperationBase = require('./operation').OperationBase;
+
+class BulkWriteOperation extends OperationBase {
+  constructor(collection, operations, options) {
+    super(options);
+
+    this.collection = collection;
+    this.operations = operations;
+  }
+
+  execute(callback) {
+    const coll = this.collection;
+    const operations = this.operations;
+    let options = this.options;
+
+    // Add ignoreUndfined
+    if (coll.s.options.ignoreUndefined) {
+      options = Object.assign({}, options);
+      options.ignoreUndefined = coll.s.options.ignoreUndefined;
+    }
+
+    // Create the bulk operation
+    const bulk =
+      options.ordered === true || options.ordered == null
+        ? coll.initializeOrderedBulkOp(options)
+        : coll.initializeUnorderedBulkOp(options);
+
+    // Do we have a collation
+    let collation = false;
+
+    // for each op go through and add to the bulk
+    try {
+      for (let i = 0; i < operations.length; i++) {
+        // Get the operation type
+        const key = Object.keys(operations[i])[0];
+        // Check if we have a collation
+        if (operations[i][key].collation) {
+          collation = true;
+        }
+
+        // Pass to the raw bulk
+        bulk.raw(operations[i]);
+      }
+    } catch (err) {
+      return callback(err, null);
+    }
+
+    // Final options for retryable writes and write concern
+    let finalOptions = Object.assign({}, options);
+    finalOptions = applyRetryableWrites(finalOptions, coll.s.db);
+    finalOptions = applyWriteConcern(finalOptions, { db: coll.s.db, collection: coll }, options);
+
+    const writeCon = finalOptions.writeConcern ? finalOptions.writeConcern : {};
+    const capabilities = coll.s.topology.capabilities();
+
+    // Did the user pass in a collation, check if our write server supports it
+    if (collation && capabilities && !capabilities.commandsTakeCollation) {
+      return callback(new MongoError('server/primary/mongos does not support collation'));
+    }
+
+    // Execute the bulk
+    bulk.execute(writeCon, finalOptions, (err, r) => {
+      // We have connection level error
+      if (!r && err) {
+        return callback(err, null);
+      }
+
+      r.insertedCount = r.nInserted;
+      r.matchedCount = r.nMatched;
+      r.modifiedCount = r.nModified || 0;
+      r.deletedCount = r.nRemoved;
+      r.upsertedCount = r.getUpsertedIds().length;
+      r.upsertedIds = {};
+      r.insertedIds = {};
+
+      // Update the n
+      r.n = r.insertedCount;
+
+      // Inserted documents
+      const inserted = r.getInsertedIds();
+      // Map inserted ids
+      for (let i = 0; i < inserted.length; i++) {
+        r.insertedIds[inserted[i].index] = inserted[i]._id;
+      }
+
+      // Upserted documents
+      const upserted = r.getUpsertedIds();
+      // Map upserted ids
+      for (let i = 0; i < upserted.length; i++) {
+        r.upsertedIds[upserted[i].index] = upserted[i]._id;
+      }
+
+      // Return the results
+      callback(null, r);
+    });
+  }
+}
+
+module.exports = BulkWriteOperation;
diff --git a/node_modules/mongodb/lib/operations/collection_ops.js b/node_modules/mongodb/lib/operations/collection_ops.js
new file mode 100644
index 0000000..655bd70
--- /dev/null
+++ b/node_modules/mongodb/lib/operations/collection_ops.js
@@ -0,0 +1,353 @@
+'use strict';
+
+const applyWriteConcern = require('../utils').applyWriteConcern;
+const Code = require('../core').BSON.Code;
+const createIndexDb = require('./db_ops').createIndex;
+const decorateWithCollation = require('../utils').decorateWithCollation;
+const decorateWithReadConcern = require('../utils').decorateWithReadConcern;
+const ensureIndexDb = require('./db_ops').ensureIndex;
+const evaluate = require('./db_ops').evaluate;
+const executeCommand = require('./db_ops').executeCommand;
+const handleCallback = require('../utils').handleCallback;
+const indexInformationDb = require('./db_ops').indexInformation;
+const Long = require('../core').BSON.Long;
+const MongoError = require('../core').MongoError;
+const ReadPreference = require('../core').ReadPreference;
+const insertDocuments = require('./common_functions').insertDocuments;
+const updateDocuments = require('./common_functions').updateDocuments;
+
+/**
+ * Group function helper
+ * @ignore
+ */
+// var groupFunction = function () {
+//   var c = db[ns].find(condition);
+//   var map = new Map();
+//   var reduce_function = reduce;
+//
+//   while (c.hasNext()) {
+//     var obj = c.next();
+//     var key = {};
+//
+//     for (var i = 0, len = keys.length; i < len; ++i) {
+//       var k = keys[i];
+//       key[k] = obj[k];
+//     }
+//
+//     var aggObj = map.get(key);
+//
+//     if (aggObj == null) {
+//       var newObj = Object.extend({}, key);
+//       aggObj = Object.extend(newObj, initial);
+//       map.put(key, aggObj);
+//     }
+//
+//     reduce_function(obj, aggObj);
+//   }
+//
+//   return { "result": map.values() };
+// }.toString();
+const groupFunction =
+  'function () {\nvar c = db[ns].find(condition);\nvar map = new Map();\nvar reduce_function = reduce;\n\nwhile (c.hasNext()) {\nvar obj = c.next();\nvar key = {};\n\nfor (var i = 0, len = keys.length; i < len; ++i) {\nvar k = keys[i];\nkey[k] = obj[k];\n}\n\nvar aggObj = map.get(key);\n\nif (aggObj == null) {\nvar newObj = Object.extend({}, key);\naggObj = Object.extend(newObj, initial);\nmap.put(key, aggObj);\n}\n\nreduce_function(obj, aggObj);\n}\n\nreturn { "result": map.values() };\n}';
+
+/**
+ * Create an index on the db and collection.
+ *
+ * @method
+ * @param {Collection} a Collection instance.
+ * @param {(string|object)} fieldOrSpec Defines the index.
+ * @param {object} [options] Optional settings. See Collection.prototype.createIndex for a list of options.
+ * @param {Collection~resultCallback} [callback] The command result callback
+ */
+function createIndex(coll, fieldOrSpec, options, callback) {
+  createIndexDb(coll.s.db, coll.collectionName, fieldOrSpec, options, callback);
+}
+
+/**
+ * Create multiple indexes in the collection. This method is only supported for
+ * MongoDB 2.6 or higher. Earlier version of MongoDB will throw a command not supported
+ * error. Index specifications are defined at http://docs.mongodb.org/manual/reference/command/createIndexes/.
+ *
+ * @method
+ * @param {Collection} a Collection instance.
+ * @param {array} indexSpecs An array of index specifications to be created
+ * @param {Object} [options] Optional settings. See Collection.prototype.createIndexes for a list of options.
+ * @param {Collection~resultCallback} [callback] The command result callback
+ */
+function createIndexes(coll, indexSpecs, options, callback) {
+  const capabilities = coll.s.topology.capabilities();
+
+  // Ensure we generate the correct name if the parameter is not set
+  for (let i = 0; i < indexSpecs.length; i++) {
+    if (indexSpecs[i].name == null) {
+      const keys = [];
+
+      // Did the user pass in a collation, check if our write server supports it
+      if (indexSpecs[i].collation && capabilities && !capabilities.commandsTakeCollation) {
+        return callback(new MongoError('server/primary/mongos does not support collation'));
+      }
+
+      for (let name in indexSpecs[i].key) {
+        keys.push(`${name}_${indexSpecs[i].key[name]}`);
+      }
+
+      // Set the name
+      indexSpecs[i].name = keys.join('_');
+    }
+  }
+
+  options = Object.assign({}, options, { readPreference: ReadPreference.PRIMARY });
+
+  // Execute the index
+  executeCommand(
+    coll.s.db,
+    {
+      createIndexes: coll.collectionName,
+      indexes: indexSpecs
+    },
+    options,
+    callback
+  );
+}
+
+/**
+ * Ensure that an index exists. If the index does not exist, this function creates it.
+ *
+ * @method
+ * @param {Collection} a Collection instance.
+ * @param {(string|object)} fieldOrSpec Defines the index.
+ * @param {object} [options] Optional settings. See Collection.prototype.ensureIndex for a list of options.
+ * @param {Collection~resultCallback} [callback] The command result callback
+ */
+function ensureIndex(coll, fieldOrSpec, options, callback) {
+  ensureIndexDb(coll.s.db, coll.collectionName, fieldOrSpec, options, callback);
+}
+
+/**
+ * Run a group command across a collection.
+ *
+ * @method
+ * @param {Collection} a Collection instance.
+ * @param {(object|array|function|code)} keys An object, array or function expressing the keys to group by.
+ * @param {object} condition An optional condition that must be true for a row to be considered.
+ * @param {object} initial Initial value of the aggregation counter object.
+ * @param {(function|Code)} reduce The reduce function aggregates (reduces) the objects iterated
+ * @param {(function|Code)} finalize An optional function to be run on each item in the result set just before the item is returned.
+ * @param {boolean} command Specify if you wish to run using the internal group command or using eval, default is true.
+ * @param {object} [options] Optional settings. See Collection.prototype.group for a list of options.
+ * @param {Collection~resultCallback} [callback] The command result callback
+ * @deprecated MongoDB 3.6 or higher will no longer support the group command. We recommend rewriting using the aggregation framework.
+ */
+function group(coll, keys, condition, initial, reduce, finalize, command, options, callback) {
+  // Execute using the command
+  if (command) {
+    const reduceFunction = reduce && reduce._bsontype === 'Code' ? reduce : new Code(reduce);
+
+    const selector = {
+      group: {
+        ns: coll.collectionName,
+        $reduce: reduceFunction,
+        cond: condition,
+        initial: initial,
+        out: 'inline'
+      }
+    };
+
+    // if finalize is defined
+    if (finalize != null) selector.group['finalize'] = finalize;
+    // Set up group selector
+    if ('function' === typeof keys || (keys && keys._bsontype === 'Code')) {
+      selector.group.$keyf = keys && keys._bsontype === 'Code' ? keys : new Code(keys);
+    } else {
+      const hash = {};
+      keys.forEach(key => {
+        hash[key] = 1;
+      });
+      selector.group.key = hash;
+    }
+
+    options = Object.assign({}, options);
+    // Ensure we have the right read preference inheritance
+    options.readPreference = ReadPreference.resolve(coll, options);
+
+    // Do we have a readConcern specified
+    decorateWithReadConcern(selector, coll, options);
+
+    // Have we specified collation
+    try {
+      decorateWithCollation(selector, coll, options);
+    } catch (err) {
+      return callback(err, null);
+    }
+
+    // Execute command
+    executeCommand(coll.s.db, selector, options, (err, result) => {
+      if (err) return handleCallback(callback, err, null);
+      handleCallback(callback, null, result.retval);
+    });
+  } else {
+    // Create execution scope
+    const scope = reduce != null && reduce._bsontype === 'Code' ? reduce.scope : {};
+
+    scope.ns = coll.collectionName;
+    scope.keys = keys;
+    scope.condition = condition;
+    scope.initial = initial;
+
+    // Pass in the function text to execute within mongodb.
+    const groupfn = groupFunction.replace(/ reduce;/, reduce.toString() + ';');
+
+    evaluate(coll.s.db, new Code(groupfn, scope), null, options, (err, results) => {
+      if (err) return handleCallback(callback, err, null);
+      handleCallback(callback, null, results.result || results);
+    });
+  }
+}
+
+/**
+ * Retrieve all the indexes on the collection.
+ *
+ * @method
+ * @param {Collection} a Collection instance.
+ * @param {Object} [options] Optional settings. See Collection.prototype.indexes for a list of options.
+ * @param {Collection~resultCallback} [callback] The command result callback
+ */
+function indexes(coll, options, callback) {
+  options = Object.assign({}, { full: true }, options);
+  indexInformationDb(coll.s.db, coll.collectionName, options, callback);
+}
+
+/**
+ * Check if one or more indexes exist on the collection. This fails on the first index that doesn't exist.
+ *
+ * @method
+ * @param {Collection} a Collection instance.
+ * @param {(string|array)} indexes One or more index names to check.
+ * @param {Object} [options] Optional settings. See Collection.prototype.indexExists for a list of options.
+ * @param {Collection~resultCallback} [callback] The command result callback
+ */
+function indexExists(coll, indexes, options, callback) {
+  indexInformation(coll, options, (err, indexInformation) => {
+    // If we have an error return
+    if (err != null) return handleCallback(callback, err, null);
+    // Let's check for the index names
+    if (!Array.isArray(indexes))
+      return handleCallback(callback, null, indexInformation[indexes] != null);
+    // Check in list of indexes
+    for (let i = 0; i < indexes.length; i++) {
+      if (indexInformation[indexes[i]] == null) {
+        return handleCallback(callback, null, false);
+      }
+    }
+
+    // All keys found return true
+    return handleCallback(callback, null, true);
+  });
+}
+
+/**
+ * Retrieve this collection's index info.
+ *
+ * @method
+ * @param {Collection} a Collection instance.
+ * @param {object} [options] Optional settings. See Collection.prototype.indexInformation for a list of options.
+ * @param {Collection~resultCallback} [callback] The command result callback
+ */
+function indexInformation(coll, options, callback) {
+  indexInformationDb(coll.s.db, coll.collectionName, options, callback);
+}
+
+/**
+ * Return N parallel cursors for a collection to allow parallel reading of the entire collection. There are
+ * no ordering guarantees for returned results.
+ *
+ * @method
+ * @param {Collection} a Collection instance.
+ * @param {object} [options] Optional settings. See Collection.prototype.parallelCollectionScan for a list of options.
+ * @param {Collection~parallelCollectionScanCallback} [callback] The command result callback
+ */
+function parallelCollectionScan(coll, options, callback) {
+  // Create command object
+  const commandObject = {
+    parallelCollectionScan: coll.collectionName,
+    numCursors: options.numCursors
+  };
+
+  // Do we have a readConcern specified
+  decorateWithReadConcern(commandObject, coll, options);
+
+  // Store the raw value
+  const raw = options.raw;
+  delete options['raw'];
+
+  // Execute the command
+  executeCommand(coll.s.db, commandObject, options, (err, result) => {
+    if (err) return handleCallback(callback, err, null);
+    if (result == null)
+      return handleCallback(
+        callback,
+        new Error('no result returned for parallelCollectionScan'),
+        null
+      );
+
+    options = Object.assign({ explicitlyIgnoreSession: true }, options);
+
+    const cursors = [];
+    // Add the raw back to the option
+    if (raw) options.raw = raw;
+    // Create command cursors for each item
+    for (let i = 0; i < result.cursors.length; i++) {
+      const rawId = result.cursors[i].cursor.id;
+      // Convert cursorId to Long if needed
+      const cursorId = typeof rawId === 'number' ? Long.fromNumber(rawId) : rawId;
+      // Add a command cursor
+      cursors.push(coll.s.topology.cursor(coll.namespace, cursorId, options));
+    }
+
+    handleCallback(callback, null, cursors);
+  });
+}
+
+/**
+ * Save a document.
+ *
+ * @method
+ * @param {Collection} a Collection instance.
+ * @param {object} doc Document to save
+ * @param {object} [options] Optional settings. See Collection.prototype.save for a list of options.
+ * @param {Collection~writeOpCallback} [callback] The command result callback
+ * @deprecated use insertOne, insertMany, updateOne or updateMany
+ */
+function save(coll, doc, options, callback) {
+  // Get the write concern options
+  const finalOptions = applyWriteConcern(
+    Object.assign({}, options),
+    { db: coll.s.db, collection: coll },
+    options
+  );
+  // Establish if we need to perform an insert or update
+  if (doc._id != null) {
+    finalOptions.upsert = true;
+    return updateDocuments(coll, { _id: doc._id }, doc, finalOptions, callback);
+  }
+
+  // Insert the document
+  insertDocuments(coll, [doc], finalOptions, (err, result) => {
+    if (callback == null) return;
+    if (doc == null) return handleCallback(callback, null, null);
+    if (err) return handleCallback(callback, err, null);
+    handleCallback(callback, null, result);
+  });
+}
+
+module.exports = {
+  createIndex,
+  createIndexes,
+  ensureIndex,
+  group,
+  indexes,
+  indexExists,
+  indexInformation,
+  parallelCollectionScan,
+  save
+};
diff --git a/node_modules/mongodb/lib/operations/collections.js b/node_modules/mongodb/lib/operations/collections.js
new file mode 100644
index 0000000..eac690a
--- /dev/null
+++ b/node_modules/mongodb/lib/operations/collections.js
@@ -0,0 +1,55 @@
+'use strict';
+
+const OperationBase = require('./operation').OperationBase;
+const handleCallback = require('../utils').handleCallback;
+
+let collection;
+function loadCollection() {
+  if (!collection) {
+    collection = require('../collection');
+  }
+  return collection;
+}
+
+class CollectionsOperation extends OperationBase {
+  constructor(db, options) {
+    super(options);
+
+    this.db = db;
+  }
+
+  execute(callback) {
+    const db = this.db;
+    let options = this.options;
+
+    let Collection = loadCollection();
+
+    options = Object.assign({}, options, { nameOnly: true });
+    // Let's get the collection names
+    db.listCollections({}, options).toArray((err, documents) => {
+      if (err != null) return handleCallback(callback, err, null);
+      // Filter collections removing any illegal ones
+      documents = documents.filter(doc => {
+        return doc.name.indexOf('$') === -1;
+      });
+
+      // Return the collection objects
+      handleCallback(
+        callback,
+        null,
+        documents.map(d => {
+          return new Collection(
+            db,
+            db.s.topology,
+            db.databaseName,
+            d.name,
+            db.s.pkFactory,
+            db.s.options
+          );
+        })
+      );
+    });
+  }
+}
+
+module.exports = CollectionsOperation;
diff --git a/node_modules/mongodb/lib/operations/command.js b/node_modules/mongodb/lib/operations/command.js
new file mode 100644
index 0000000..fd18a54
--- /dev/null
+++ b/node_modules/mongodb/lib/operations/command.js
@@ -0,0 +1,119 @@
+'use strict';
+
+const Aspect = require('./operation').Aspect;
+const OperationBase = require('./operation').OperationBase;
+const applyWriteConcern = require('../utils').applyWriteConcern;
+const debugOptions = require('../utils').debugOptions;
+const handleCallback = require('../utils').handleCallback;
+const MongoError = require('../core').MongoError;
+const ReadPreference = require('../core').ReadPreference;
+const MongoDBNamespace = require('../utils').MongoDBNamespace;
+
+const debugFields = [
+  'authSource',
+  'w',
+  'wtimeout',
+  'j',
+  'native_parser',
+  'forceServerObjectId',
+  'serializeFunctions',
+  'raw',
+  'promoteLongs',
+  'promoteValues',
+  'promoteBuffers',
+  'bufferMaxEntries',
+  'numberOfRetries',
+  'retryMiliSeconds',
+  'readPreference',
+  'pkFactory',
+  'parentDb',
+  'promiseLibrary',
+  'noListener'
+];
+
+class CommandOperation extends OperationBase {
+  constructor(db, options, collection, command) {
+    super(options);
+
+    if (!this.hasAspect(Aspect.WRITE_OPERATION)) {
+      if (collection != null) {
+        this.options.readPreference = ReadPreference.resolve(collection, options);
+      } else {
+        this.options.readPreference = ReadPreference.resolve(db, options);
+      }
+    } else {
+      if (collection != null) {
+        applyWriteConcern(this.options, { db, coll: collection }, this.options);
+      } else {
+        applyWriteConcern(this.options, { db }, this.options);
+      }
+      this.options.readPreference = ReadPreference.primary;
+    }
+
+    this.db = db;
+
+    if (command != null) {
+      this.command = command;
+    }
+
+    if (collection != null) {
+      this.collection = collection;
+    }
+  }
+
+  _buildCommand() {
+    if (this.command != null) {
+      return this.command;
+    }
+  }
+
+  execute(callback) {
+    const db = this.db;
+    const options = Object.assign({}, this.options);
+
+    // Did the user destroy the topology
+    if (db.serverConfig && db.serverConfig.isDestroyed()) {
+      return callback(new MongoError('topology was destroyed'));
+    }
+
+    let command;
+    try {
+      command = this._buildCommand();
+    } catch (e) {
+      return callback(e);
+    }
+
+    // Get the db name we are executing against
+    const dbName = options.dbName || options.authdb || db.databaseName;
+
+    // Convert the readPreference if its not a write
+    if (this.hasAspect(Aspect.WRITE_OPERATION)) {
+      if (options.writeConcern && (!options.session || !options.session.inTransaction())) {
+        command.writeConcern = options.writeConcern;
+      }
+    }
+
+    // Debug information
+    if (db.s.logger.isDebug()) {
+      db.s.logger.debug(
+        `executing command ${JSON.stringify(
+          command
+        )} against ${dbName}.$cmd with options [${JSON.stringify(
+          debugOptions(debugFields, options)
+        )}]`
+      );
+    }
+
+    const namespace =
+      this.namespace != null ? this.namespace : new MongoDBNamespace(dbName, '$cmd');
+
+    // Execute command
+    db.s.topology.command(namespace, command, options, (err, result) => {
+      if (err) return handleCallback(callback, err);
+      if (options.full) return handleCallback(callback, null, result);
+      handleCallback(callback, null, result.result);
+    });
+  }
+}
+
+module.exports = CommandOperation;
diff --git a/node_modules/mongodb/lib/operations/command_v2.js b/node_modules/mongodb/lib/operations/command_v2.js
new file mode 100644
index 0000000..e59122a
--- /dev/null
+++ b/node_modules/mongodb/lib/operations/command_v2.js
@@ -0,0 +1,110 @@
+'use strict';
+
+const Aspect = require('./operation').Aspect;
+const OperationBase = require('./operation').OperationBase;
+const ReadPreference = require('../core').ReadPreference;
+const ReadConcern = require('../read_concern');
+const WriteConcern = require('../write_concern');
+const maxWireVersion = require('../core/utils').maxWireVersion;
+const commandSupportsReadConcern = require('../core/sessions').commandSupportsReadConcern;
+const MongoError = require('../core/error').MongoError;
+
+const SUPPORTS_WRITE_CONCERN_AND_COLLATION = 5;
+
+class CommandOperationV2 extends OperationBase {
+  constructor(parent, options, operationOptions) {
+    super(options);
+
+    this.ns = parent.s.namespace.withCollection('$cmd');
+    const propertyProvider = this.hasAspect(Aspect.NO_INHERIT_OPTIONS) ? undefined : parent;
+    this.readPreference = this.hasAspect(Aspect.WRITE_OPERATION)
+      ? ReadPreference.primary
+      : ReadPreference.resolve(propertyProvider, this.options);
+    this.readConcern = resolveReadConcern(propertyProvider, this.options);
+    this.writeConcern = resolveWriteConcern(propertyProvider, this.options);
+    this.explain = false;
+
+    if (operationOptions && typeof operationOptions.fullResponse === 'boolean') {
+      this.fullResponse = true;
+    }
+
+    // TODO: A lot of our code depends on having the read preference in the options. This should
+    //       go away, but also requires massive test rewrites.
+    this.options.readPreference = this.readPreference;
+
+    // TODO(NODE-2056): make logger another "inheritable" property
+    if (parent.s.logger) {
+      this.logger = parent.s.logger;
+    } else if (parent.s.db && parent.s.db.logger) {
+      this.logger = parent.s.db.logger;
+    }
+  }
+
+  executeCommand(server, cmd, callback) {
+    // TODO: consider making this a non-enumerable property
+    this.server = server;
+
+    const options = this.options;
+    const serverWireVersion = maxWireVersion(server);
+    const inTransaction = this.session && this.session.inTransaction();
+
+    if (this.readConcern && commandSupportsReadConcern(cmd) && !inTransaction) {
+      Object.assign(cmd, { readConcern: this.readConcern });
+    }
+
+    if (options.collation && serverWireVersion < SUPPORTS_WRITE_CONCERN_AND_COLLATION) {
+      callback(
+        new MongoError(
+          `Server ${server.name}, which reports wire version ${serverWireVersion}, does not support collation`
+        )
+      );
+      return;
+    }
+
+    if (serverWireVersion >= SUPPORTS_WRITE_CONCERN_AND_COLLATION) {
+      if (this.writeConcern && this.hasAspect(Aspect.WRITE_OPERATION)) {
+        Object.assign(cmd, { writeConcern: this.writeConcern });
+      }
+
+      if (options.collation && typeof options.collation === 'object') {
+        Object.assign(cmd, { collation: options.collation });
+      }
+    }
+
+    if (typeof options.maxTimeMS === 'number') {
+      cmd.maxTimeMS = options.maxTimeMS;
+    }
+
+    if (typeof options.comment === 'string') {
+      cmd.comment = options.comment;
+    }
+
+    if (this.logger && this.logger.isDebug()) {
+      this.logger.debug(`executing command ${JSON.stringify(cmd)} against ${this.ns}`);
+    }
+
+    server.command(this.ns.toString(), cmd, this.options, (err, result) => {
+      if (err) {
+        callback(err, null);
+        return;
+      }
+
+      if (this.fullResponse) {
+        callback(null, result);
+        return;
+      }
+
+      callback(null, result.result);
+    });
+  }
+}
+
+function resolveWriteConcern(parent, options) {
+  return WriteConcern.fromOptions(options) || (parent && parent.writeConcern);
+}
+
+function resolveReadConcern(parent, options) {
+  return ReadConcern.fromOptions(options) || (parent && parent.readConcern);
+}
+
+module.exports = CommandOperationV2;
diff --git a/node_modules/mongodb/lib/operations/common_functions.js b/node_modules/mongodb/lib/operations/common_functions.js
new file mode 100644
index 0000000..a02c53d
--- /dev/null
+++ b/node_modules/mongodb/lib/operations/common_functions.js
@@ -0,0 +1,412 @@
+'use strict';
+
+const applyRetryableWrites = require('../utils').applyRetryableWrites;
+const applyWriteConcern = require('../utils').applyWriteConcern;
+const decorateWithCollation = require('../utils').decorateWithCollation;
+const decorateWithReadConcern = require('../utils').decorateWithReadConcern;
+const executeCommand = require('./db_ops').executeCommand;
+const formattedOrderClause = require('../utils').formattedOrderClause;
+const handleCallback = require('../utils').handleCallback;
+const MongoError = require('../core').MongoError;
+const ReadPreference = require('../core').ReadPreference;
+const toError = require('../utils').toError;
+const CursorState = require('../core/cursor').CursorState;
+
+/**
+ * Build the count command.
+ *
+ * @method
+ * @param {collectionOrCursor} an instance of a collection or cursor
+ * @param {object} query The query for the count.
+ * @param {object} [options] Optional settings. See Collection.prototype.count and Cursor.prototype.count for a list of options.
+ */
+function buildCountCommand(collectionOrCursor, query, options) {
+  const skip = options.skip;
+  const limit = options.limit;
+  let hint = options.hint;
+  const maxTimeMS = options.maxTimeMS;
+  query = query || {};
+
+  // Final query
+  const cmd = {
+    count: options.collectionName,
+    query: query
+  };
+
+  if (collectionOrCursor.s.numberOfRetries) {
+    // collectionOrCursor is a cursor
+    if (collectionOrCursor.options.hint) {
+      hint = collectionOrCursor.options.hint;
+    } else if (collectionOrCursor.cmd.hint) {
+      hint = collectionOrCursor.cmd.hint;
+    }
+    decorateWithCollation(cmd, collectionOrCursor, collectionOrCursor.cmd);
+  } else {
+    decorateWithCollation(cmd, collectionOrCursor, options);
+  }
+
+  // Add limit, skip and maxTimeMS if defined
+  if (typeof skip === 'number') cmd.skip = skip;
+  if (typeof limit === 'number') cmd.limit = limit;
+  if (typeof maxTimeMS === 'number') cmd.maxTimeMS = maxTimeMS;
+  if (hint) cmd.hint = hint;
+
+  // Do we have a readConcern specified
+  decorateWithReadConcern(cmd, collectionOrCursor);
+
+  return cmd;
+}
+
+function deleteCallback(err, r, callback) {
+  if (callback == null) return;
+  if (err && callback) return callback(err);
+  if (r == null) return callback(null, { result: { ok: 1 } });
+  r.deletedCount = r.result.n;
+  if (callback) callback(null, r);
+}
+
+/**
+ * Find and update a document.
+ *
+ * @method
+ * @param {Collection} a Collection instance.
+ * @param {object} query Query object to locate the object to modify.
+ * @param {array} sort If multiple docs match, choose the first one in the specified sort order as the object to manipulate.
+ * @param {object} doc The fields/vals to be updated.
+ * @param {object} [options] Optional settings. See Collection.prototype.findAndModify for a list of options.
+ * @param {Collection~findAndModifyCallback} [callback] The command result callback
+ * @deprecated use findOneAndUpdate, findOneAndReplace or findOneAndDelete instead
+ */
+function findAndModify(coll, query, sort, doc, options, callback) {
+  // Create findAndModify command object
+  const queryObject = {
+    findAndModify: coll.collectionName,
+    query: query
+  };
+
+  sort = formattedOrderClause(sort);
+  if (sort) {
+    queryObject.sort = sort;
+  }
+
+  queryObject.new = options.new ? true : false;
+  queryObject.remove = options.remove ? true : false;
+  queryObject.upsert = options.upsert ? true : false;
+
+  const projection = options.projection || options.fields;
+
+  if (projection) {
+    queryObject.fields = projection;
+  }
+
+  if (options.arrayFilters) {
+    queryObject.arrayFilters = options.arrayFilters;
+    delete options.arrayFilters;
+  }
+
+  if (doc && !options.remove) {
+    queryObject.update = doc;
+  }
+
+  if (options.maxTimeMS) queryObject.maxTimeMS = options.maxTimeMS;
+
+  // Either use override on the function, or go back to default on either the collection
+  // level or db
+  options.serializeFunctions = options.serializeFunctions || coll.s.serializeFunctions;
+
+  // No check on the documents
+  options.checkKeys = false;
+
+  // Final options for retryable writes and write concern
+  let finalOptions = Object.assign({}, options);
+  finalOptions = applyRetryableWrites(finalOptions, coll.s.db);
+  finalOptions = applyWriteConcern(finalOptions, { db: coll.s.db, collection: coll }, options);
+
+  // Decorate the findAndModify command with the write Concern
+  if (finalOptions.writeConcern) {
+    queryObject.writeConcern = finalOptions.writeConcern;
+  }
+
+  // Have we specified bypassDocumentValidation
+  if (finalOptions.bypassDocumentValidation === true) {
+    queryObject.bypassDocumentValidation = finalOptions.bypassDocumentValidation;
+  }
+
+  finalOptions.readPreference = ReadPreference.primary;
+
+  // Have we specified collation
+  try {
+    decorateWithCollation(queryObject, coll, finalOptions);
+  } catch (err) {
+    return callback(err, null);
+  }
+
+  // Execute the command
+  executeCommand(coll.s.db, queryObject, finalOptions, (err, result) => {
+    if (err) return handleCallback(callback, err, null);
+
+    return handleCallback(callback, null, result);
+  });
+}
+
+/**
+ * Retrieves this collections index info.
+ *
+ * @method
+ * @param {Db} db The Db instance on which to retrieve the index info.
+ * @param {string} name The name of the collection.
+ * @param {object} [options] Optional settings. See Db.prototype.indexInformation for a list of options.
+ * @param {Db~resultCallback} [callback] The command result callback
+ */
+function indexInformation(db, name, options, callback) {
+  // If we specified full information
+  const full = options['full'] == null ? false : options['full'];
+
+  // Did the user destroy the topology
+  if (db.serverConfig && db.serverConfig.isDestroyed())
+    return callback(new MongoError('topology was destroyed'));
+  // Process all the results from the index command and collection
+  function processResults(indexes) {
+    // Contains all the information
+    let info = {};
+    // Process all the indexes
+    for (let i = 0; i < indexes.length; i++) {
+      const index = indexes[i];
+      // Let's unpack the object
+      info[index.name] = [];
+      for (let name in index.key) {
+        info[index.name].push([name, index.key[name]]);
+      }
+    }
+
+    return info;
+  }
+
+  // Get the list of indexes of the specified collection
+  db.collection(name)
+    .listIndexes(options)
+    .toArray((err, indexes) => {
+      if (err) return callback(toError(err));
+      if (!Array.isArray(indexes)) return handleCallback(callback, null, []);
+      if (full) return handleCallback(callback, null, indexes);
+      handleCallback(callback, null, processResults(indexes));
+    });
+}
+
+function prepareDocs(coll, docs, options) {
+  const forceServerObjectId =
+    typeof options.forceServerObjectId === 'boolean'
+      ? options.forceServerObjectId
+      : coll.s.db.options.forceServerObjectId;
+
+  // no need to modify the docs if server sets the ObjectId
+  if (forceServerObjectId === true) {
+    return docs;
+  }
+
+  return docs.map(doc => {
+    if (forceServerObjectId !== true && doc._id == null) {
+      doc._id = coll.s.pkFactory.createPk();
+    }
+
+    return doc;
+  });
+}
+
+// Get the next available document from the cursor, returns null if no more documents are available.
+function nextObject(cursor, callback) {
+  if (cursor.s.state === CursorState.CLOSED || (cursor.isDead && cursor.isDead())) {
+    return handleCallback(
+      callback,
+      MongoError.create({ message: 'Cursor is closed', driver: true })
+    );
+  }
+
+  if (cursor.s.state === CursorState.INIT && cursor.cmd && cursor.cmd.sort) {
+    try {
+      cursor.cmd.sort = formattedOrderClause(cursor.cmd.sort);
+    } catch (err) {
+      return handleCallback(callback, err);
+    }
+  }
+
+  // Get the next object
+  cursor._next((err, doc) => {
+    cursor.s.state = CursorState.OPEN;
+    if (err) return handleCallback(callback, err);
+    handleCallback(callback, null, doc);
+  });
+}
+
+function insertDocuments(coll, docs, options, callback) {
+  if (typeof options === 'function') (callback = options), (options = {});
+  options = options || {};
+  // Ensure we are operating on an array op docs
+  docs = Array.isArray(docs) ? docs : [docs];
+
+  // Final options for retryable writes and write concern
+  let finalOptions = Object.assign({}, options);
+  finalOptions = applyRetryableWrites(finalOptions, coll.s.db);
+  finalOptions = applyWriteConcern(finalOptions, { db: coll.s.db, collection: coll }, options);
+
+  // If keep going set unordered
+  if (finalOptions.keepGoing === true) finalOptions.ordered = false;
+  finalOptions.serializeFunctions = options.serializeFunctions || coll.s.serializeFunctions;
+
+  docs = prepareDocs(coll, docs, options);
+
+  // File inserts
+  coll.s.topology.insert(coll.s.namespace, docs, finalOptions, (err, result) => {
+    if (callback == null) return;
+    if (err) return handleCallback(callback, err);
+    if (result == null) return handleCallback(callback, null, null);
+    if (result.result.code) return handleCallback(callback, toError(result.result));
+    if (result.result.writeErrors)
+      return handleCallback(callback, toError(result.result.writeErrors[0]));
+    // Add docs to the list
+    result.ops = docs;
+    // Return the results
+    handleCallback(callback, null, result);
+  });
+}
+
+function removeDocuments(coll, selector, options, callback) {
+  if (typeof options === 'function') {
+    (callback = options), (options = {});
+  } else if (typeof selector === 'function') {
+    callback = selector;
+    options = {};
+    selector = {};
+  }
+
+  // Create an empty options object if the provided one is null
+  options = options || {};
+
+  // Final options for retryable writes and write concern
+  let finalOptions = Object.assign({}, options);
+  finalOptions = applyRetryableWrites(finalOptions, coll.s.db);
+  finalOptions = applyWriteConcern(finalOptions, { db: coll.s.db, collection: coll }, options);
+
+  // If selector is null set empty
+  if (selector == null) selector = {};
+
+  // Build the op
+  const op = { q: selector, limit: 0 };
+  if (options.single) {
+    op.limit = 1;
+  } else if (finalOptions.retryWrites) {
+    finalOptions.retryWrites = false;
+  }
+  if (options.hint) {
+    op.hint = options.hint;
+  }
+
+  // Have we specified collation
+  try {
+    decorateWithCollation(finalOptions, coll, options);
+  } catch (err) {
+    return callback(err, null);
+  }
+
+  // Execute the remove
+  coll.s.topology.remove(coll.s.namespace, [op], finalOptions, (err, result) => {
+    if (callback == null) return;
+    if (err) return handleCallback(callback, err, null);
+    if (result == null) return handleCallback(callback, null, null);
+    if (result.result.code) return handleCallback(callback, toError(result.result));
+    if (result.result.writeErrors) {
+      return handleCallback(callback, toError(result.result.writeErrors[0]));
+    }
+
+    // Return the results
+    handleCallback(callback, null, result);
+  });
+}
+
+function updateDocuments(coll, selector, document, options, callback) {
+  if ('function' === typeof options) (callback = options), (options = null);
+  if (options == null) options = {};
+  if (!('function' === typeof callback)) callback = null;
+
+  // If we are not providing a selector or document throw
+  if (selector == null || typeof selector !== 'object')
+    return callback(toError('selector must be a valid JavaScript object'));
+  if (document == null || typeof document !== 'object')
+    return callback(toError('document must be a valid JavaScript object'));
+
+  // Final options for retryable writes and write concern
+  let finalOptions = Object.assign({}, options);
+  finalOptions = applyRetryableWrites(finalOptions, coll.s.db);
+  finalOptions = applyWriteConcern(finalOptions, { db: coll.s.db, collection: coll }, options);
+
+  // Do we return the actual result document
+  // Either use override on the function, or go back to default on either the collection
+  // level or db
+  finalOptions.serializeFunctions = options.serializeFunctions || coll.s.serializeFunctions;
+
+  // Execute the operation
+  const op = { q: selector, u: document };
+  op.upsert = options.upsert !== void 0 ? !!options.upsert : false;
+  op.multi = options.multi !== void 0 ? !!options.multi : false;
+
+  if (options.hint) {
+    op.hint = options.hint;
+  }
+
+  if (finalOptions.arrayFilters) {
+    op.arrayFilters = finalOptions.arrayFilters;
+    delete finalOptions.arrayFilters;
+  }
+
+  if (finalOptions.retryWrites && op.multi) {
+    finalOptions.retryWrites = false;
+  }
+
+  // Have we specified collation
+  try {
+    decorateWithCollation(finalOptions, coll, options);
+  } catch (err) {
+    return callback(err, null);
+  }
+
+  // Update options
+  coll.s.topology.update(coll.s.namespace, [op], finalOptions, (err, result) => {
+    if (callback == null) return;
+    if (err) return handleCallback(callback, err, null);
+    if (result == null) return handleCallback(callback, null, null);
+    if (result.result.code) return handleCallback(callback, toError(result.result));
+    if (result.result.writeErrors)
+      return handleCallback(callback, toError(result.result.writeErrors[0]));
+    // Return the results
+    handleCallback(callback, null, result);
+  });
+}
+
+function updateCallback(err, r, callback) {
+  if (callback == null) return;
+  if (err) return callback(err);
+  if (r == null) return callback(null, { result: { ok: 1 } });
+  r.modifiedCount = r.result.nModified != null ? r.result.nModified : r.result.n;
+  r.upsertedId =
+    Array.isArray(r.result.upserted) && r.result.upserted.length > 0
+      ? r.result.upserted[0] // FIXME(major): should be `r.result.upserted[0]._id`
+      : null;
+  r.upsertedCount =
+    Array.isArray(r.result.upserted) && r.result.upserted.length ? r.result.upserted.length : 0;
+  r.matchedCount =
+    Array.isArray(r.result.upserted) && r.result.upserted.length > 0 ? 0 : r.result.n;
+  callback(null, r);
+}
+
+module.exports = {
+  buildCountCommand,
+  deleteCallback,
+  findAndModify,
+  indexInformation,
+  nextObject,
+  prepareDocs,
+  insertDocuments,
+  removeDocuments,
+  updateDocuments,
+  updateCallback
+};
diff --git a/node_modules/mongodb/lib/operations/connect.js b/node_modules/mongodb/lib/operations/connect.js
new file mode 100644
index 0000000..2c3e8bd
--- /dev/null
+++ b/node_modules/mongodb/lib/operations/connect.js
@@ -0,0 +1,806 @@
+'use strict';
+
+const deprecate = require('util').deprecate;
+const Logger = require('../core').Logger;
+const MongoCredentials = require('../core').MongoCredentials;
+const MongoError = require('../core').MongoError;
+const Mongos = require('../topologies/mongos');
+const NativeTopology = require('../topologies/native_topology');
+const parse = require('../core').parseConnectionString;
+const ReadConcern = require('../read_concern');
+const ReadPreference = require('../core').ReadPreference;
+const ReplSet = require('../topologies/replset');
+const Server = require('../topologies/server');
+const ServerSessionPool = require('../core').Sessions.ServerSessionPool;
+const emitDeprecationWarning = require('../utils').emitDeprecationWarning;
+const fs = require('fs');
+const BSON = require('../core/connection/utils').retrieveBSON();
+const CMAP_EVENT_NAMES = require('../cmap/events').CMAP_EVENT_NAMES;
+
+let client;
+function loadClient() {
+  if (!client) {
+    client = require('../mongo_client');
+  }
+  return client;
+}
+
+const legacyParse = deprecate(
+  require('../url_parser'),
+  'current URL string parser is deprecated, and will be removed in a future version. ' +
+    'To use the new parser, pass option { useNewUrlParser: true } to MongoClient.connect.'
+);
+
+const AUTH_MECHANISM_INTERNAL_MAP = {
+  DEFAULT: 'default',
+  PLAIN: 'plain',
+  GSSAPI: 'gssapi',
+  'MONGODB-CR': 'mongocr',
+  'MONGODB-X509': 'x509',
+  'MONGODB-AWS': 'mongodb-aws',
+  'SCRAM-SHA-1': 'scram-sha-1',
+  'SCRAM-SHA-256': 'scram-sha-256'
+};
+
+const monitoringEvents = [
+  'timeout',
+  'close',
+  'serverOpening',
+  'serverDescriptionChanged',
+  'serverHeartbeatStarted',
+  'serverHeartbeatSucceeded',
+  'serverHeartbeatFailed',
+  'serverClosed',
+  'topologyOpening',
+  'topologyClosed',
+  'topologyDescriptionChanged',
+  'commandStarted',
+  'commandSucceeded',
+  'commandFailed',
+  'joined',
+  'left',
+  'ping',
+  'ha',
+  'all',
+  'fullsetup',
+  'open'
+];
+
+const VALID_AUTH_MECHANISMS = new Set([
+  'DEFAULT',
+  'PLAIN',
+  'GSSAPI',
+  'MONGODB-CR',
+  'MONGODB-X509',
+  'MONGODB-AWS',
+  'SCRAM-SHA-1',
+  'SCRAM-SHA-256'
+]);
+
+const validOptionNames = [
+  'poolSize',
+  'ssl',
+  'sslValidate',
+  'sslCA',
+  'sslCert',
+  'sslKey',
+  'sslPass',
+  'sslCRL',
+  'autoReconnect',
+  'noDelay',
+  'keepAlive',
+  'keepAliveInitialDelay',
+  'connectTimeoutMS',
+  'family',
+  'socketTimeoutMS',
+  'reconnectTries',
+  'reconnectInterval',
+  'ha',
+  'haInterval',
+  'replicaSet',
+  'secondaryAcceptableLatencyMS',
+  'acceptableLatencyMS',
+  'connectWithNoPrimary',
+  'authSource',
+  'w',
+  'wtimeout',
+  'j',
+  'forceServerObjectId',
+  'serializeFunctions',
+  'ignoreUndefined',
+  'raw',
+  'bufferMaxEntries',
+  'readPreference',
+  'pkFactory',
+  'promiseLibrary',
+  'readConcern',
+  'maxStalenessSeconds',
+  'loggerLevel',
+  'logger',
+  'promoteValues',
+  'promoteBuffers',
+  'promoteLongs',
+  'domainsEnabled',
+  'checkServerIdentity',
+  'validateOptions',
+  'appname',
+  'auth',
+  'user',
+  'password',
+  'authMechanism',
+  'compression',
+  'fsync',
+  'readPreferenceTags',
+  'numberOfRetries',
+  'auto_reconnect',
+  'minSize',
+  'monitorCommands',
+  'retryWrites',
+  'retryReads',
+  'useNewUrlParser',
+  'useUnifiedTopology',
+  'serverSelectionTimeoutMS',
+  'useRecoveryToken',
+  'autoEncryption',
+  'driverInfo',
+  'tls',
+  'tlsInsecure',
+  'tlsinsecure',
+  'tlsAllowInvalidCertificates',
+  'tlsAllowInvalidHostnames',
+  'tlsCAFile',
+  'tlsCertificateFile',
+  'tlsCertificateKeyFile',
+  'tlsCertificateKeyFilePassword',
+  'minHeartbeatFrequencyMS',
+  'heartbeatFrequencyMS',
+  'directConnection',
+  'appName',
+
+  // CMAP options
+  'maxPoolSize',
+  'minPoolSize',
+  'maxIdleTimeMS',
+  'waitQueueTimeoutMS'
+];
+
+const ignoreOptionNames = ['native_parser'];
+const legacyOptionNames = ['server', 'replset', 'replSet', 'mongos', 'db'];
+
+// Validate options object
+function validOptions(options) {
+  const _validOptions = validOptionNames.concat(legacyOptionNames);
+
+  for (const name in options) {
+    if (ignoreOptionNames.indexOf(name) !== -1) {
+      continue;
+    }
+
+    if (_validOptions.indexOf(name) === -1) {
+      if (options.validateOptions) {
+        return new MongoError(`option ${name} is not supported`);
+      } else {
+        console.warn(`the options [${name}] is not supported`);
+      }
+    }
+
+    if (legacyOptionNames.indexOf(name) !== -1) {
+      console.warn(
+        `the server/replset/mongos/db options are deprecated, ` +
+          `all their options are supported at the top level of the options object [${validOptionNames}]`
+      );
+    }
+  }
+}
+
+const LEGACY_OPTIONS_MAP = validOptionNames.reduce((obj, name) => {
+  obj[name.toLowerCase()] = name;
+  return obj;
+}, {});
+
+function addListeners(mongoClient, topology) {
+  topology.on('authenticated', createListener(mongoClient, 'authenticated'));
+  topology.on('error', createListener(mongoClient, 'error'));
+  topology.on('timeout', createListener(mongoClient, 'timeout'));
+  topology.on('close', createListener(mongoClient, 'close'));
+  topology.on('parseError', createListener(mongoClient, 'parseError'));
+  topology.once('open', createListener(mongoClient, 'open'));
+  topology.once('fullsetup', createListener(mongoClient, 'fullsetup'));
+  topology.once('all', createListener(mongoClient, 'all'));
+  topology.on('reconnect', createListener(mongoClient, 'reconnect'));
+}
+
+function assignTopology(client, topology) {
+  client.topology = topology;
+
+  if (!(topology instanceof NativeTopology)) {
+    topology.s.sessionPool = new ServerSessionPool(topology.s.coreTopology);
+  }
+}
+
+// Clear out all events
+function clearAllEvents(topology) {
+  monitoringEvents.forEach(event => topology.removeAllListeners(event));
+}
+
+// Collect all events in order from SDAM
+function collectEvents(mongoClient, topology) {
+  let MongoClient = loadClient();
+  const collectedEvents = [];
+
+  if (mongoClient instanceof MongoClient) {
+    monitoringEvents.forEach(event => {
+      topology.on(event, (object1, object2) => {
+        if (event === 'open') {
+          collectedEvents.push({ event: event, object1: mongoClient });
+        } else {
+          collectedEvents.push({ event: event, object1: object1, object2: object2 });
+        }
+      });
+    });
+  }
+
+  return collectedEvents;
+}
+
+function resolveTLSOptions(options) {
+  if (options.tls == null) {
+    return;
+  }
+
+  ['sslCA', 'sslKey', 'sslCert'].forEach(optionName => {
+    if (options[optionName]) {
+      options[optionName] = fs.readFileSync(options[optionName]);
+    }
+  });
+}
+
+const emitDeprecationForNonUnifiedTopology = deprecate(() => {},
+'current Server Discovery and Monitoring engine is deprecated, and will be removed in a future version. ' + 'To use the new Server Discover and Monitoring engine, pass option { useUnifiedTopology: true } to the MongoClient constructor.');
+
+function connect(mongoClient, url, options, callback) {
+  options = Object.assign({}, options);
+
+  // If callback is null throw an exception
+  if (callback == null) {
+    throw new Error('no callback function provided');
+  }
+
+  let didRequestAuthentication = false;
+  const logger = Logger('MongoClient', options);
+
+  // Did we pass in a Server/ReplSet/Mongos
+  if (url instanceof Server || url instanceof ReplSet || url instanceof Mongos) {
+    return connectWithUrl(mongoClient, url, options, connectCallback);
+  }
+
+  const useNewUrlParser = options.useNewUrlParser !== false;
+
+  const parseFn = useNewUrlParser ? parse : legacyParse;
+  const transform = useNewUrlParser ? transformUrlOptions : legacyTransformUrlOptions;
+
+  parseFn(url, options, (err, _object) => {
+    // Do not attempt to connect if parsing error
+    if (err) return callback(err);
+
+    // Flatten
+    const object = transform(_object);
+
+    // Parse the string
+    const _finalOptions = createUnifiedOptions(object, options);
+
+    // Check if we have connection and socket timeout set
+    if (_finalOptions.socketTimeoutMS == null) _finalOptions.socketTimeoutMS = 0;
+    if (_finalOptions.connectTimeoutMS == null) _finalOptions.connectTimeoutMS = 10000;
+    if (_finalOptions.retryWrites == null) _finalOptions.retryWrites = true;
+    if (_finalOptions.useRecoveryToken == null) _finalOptions.useRecoveryToken = true;
+    if (_finalOptions.readPreference == null) _finalOptions.readPreference = 'primary';
+
+    if (_finalOptions.db_options && _finalOptions.db_options.auth) {
+      delete _finalOptions.db_options.auth;
+    }
+
+    // `journal` should be translated to `j` for the driver
+    if (_finalOptions.journal != null) {
+      _finalOptions.j = _finalOptions.journal;
+      _finalOptions.journal = undefined;
+    }
+
+    // resolve tls options if needed
+    resolveTLSOptions(_finalOptions);
+
+    // Store the merged options object
+    mongoClient.s.options = _finalOptions;
+
+    // Failure modes
+    if (object.servers.length === 0) {
+      return callback(new Error('connection string must contain at least one seed host'));
+    }
+
+    if (_finalOptions.auth && !_finalOptions.credentials) {
+      try {
+        didRequestAuthentication = true;
+        _finalOptions.credentials = generateCredentials(
+          mongoClient,
+          _finalOptions.auth.user,
+          _finalOptions.auth.password,
+          _finalOptions
+        );
+      } catch (err) {
+        return callback(err);
+      }
+    }
+
+    if (_finalOptions.useUnifiedTopology) {
+      return createTopology(mongoClient, 'unified', _finalOptions, connectCallback);
+    }
+
+    emitDeprecationForNonUnifiedTopology();
+
+    // Do we have a replicaset then skip discovery and go straight to connectivity
+    if (_finalOptions.replicaSet || _finalOptions.rs_name) {
+      return createTopology(mongoClient, 'replicaset', _finalOptions, connectCallback);
+    } else if (object.servers.length > 1) {
+      return createTopology(mongoClient, 'mongos', _finalOptions, connectCallback);
+    } else {
+      return createServer(mongoClient, _finalOptions, connectCallback);
+    }
+  });
+
+  function connectCallback(err, topology) {
+    const warningMessage = `seed list contains no mongos proxies, replicaset connections requires the parameter replicaSet to be supplied in the URI or options object, mongodb://server:port/db?replicaSet=name`;
+    if (err && err.message === 'no mongos proxies found in seed list') {
+      if (logger.isWarn()) {
+        logger.warn(warningMessage);
+      }
+
+      // Return a more specific error message for MongoClient.connect
+      return callback(new MongoError(warningMessage));
+    }
+
+    if (didRequestAuthentication) {
+      mongoClient.emit('authenticated', null, true);
+    }
+
+    // Return the error and db instance
+    callback(err, topology);
+  }
+}
+
+function connectWithUrl(mongoClient, url, options, connectCallback) {
+  // Set the topology
+  assignTopology(mongoClient, url);
+
+  // Add listeners
+  addListeners(mongoClient, url);
+
+  // Propagate the events to the client
+  relayEvents(mongoClient, url);
+
+  let finalOptions = Object.assign({}, options);
+
+  // If we have a readPreference passed in by the db options, convert it from a string
+  if (typeof options.readPreference === 'string' || typeof options.read_preference === 'string') {
+    finalOptions.readPreference = new ReadPreference(
+      options.readPreference || options.read_preference
+    );
+  }
+
+  const isDoingAuth = finalOptions.user || finalOptions.password || finalOptions.authMechanism;
+  if (isDoingAuth && !finalOptions.credentials) {
+    try {
+      finalOptions.credentials = generateCredentials(
+        mongoClient,
+        finalOptions.user,
+        finalOptions.password,
+        finalOptions
+      );
+    } catch (err) {
+      return connectCallback(err, url);
+    }
+  }
+
+  return url.connect(finalOptions, connectCallback);
+}
+
+function createListener(mongoClient, event) {
+  const eventSet = new Set(['all', 'fullsetup', 'open', 'reconnect']);
+  return (v1, v2) => {
+    if (eventSet.has(event)) {
+      return mongoClient.emit(event, mongoClient);
+    }
+
+    mongoClient.emit(event, v1, v2);
+  };
+}
+
+function createServer(mongoClient, options, callback) {
+  // Pass in the promise library
+  options.promiseLibrary = mongoClient.s.promiseLibrary;
+
+  // Set default options
+  const servers = translateOptions(options);
+
+  const server = servers[0];
+
+  // Propagate the events to the client
+  const collectedEvents = collectEvents(mongoClient, server);
+
+  // Connect to topology
+  server.connect(options, (err, topology) => {
+    if (err) {
+      server.close(true);
+      return callback(err);
+    }
+    // Clear out all the collected event listeners
+    clearAllEvents(server);
+
+    // Relay all the events
+    relayEvents(mongoClient, server);
+    // Add listeners
+    addListeners(mongoClient, server);
+    // Check if we are really speaking to a mongos
+    const ismaster = topology.lastIsMaster();
+
+    // Set the topology
+    assignTopology(mongoClient, topology);
+
+    // Do we actually have a mongos
+    if (ismaster && ismaster.msg === 'isdbgrid') {
+      // Destroy the current connection
+      topology.close();
+      // Create mongos connection instead
+      return createTopology(mongoClient, 'mongos', options, callback);
+    }
+
+    // Fire all the events
+    replayEvents(mongoClient, collectedEvents);
+    // Otherwise callback
+    callback(err, topology);
+  });
+}
+
+const DEPRECATED_UNIFIED_EVENTS = new Set([
+  'reconnect',
+  'reconnectFailed',
+  'attemptReconnect',
+  'joined',
+  'left',
+  'ping',
+  'ha',
+  'all',
+  'fullsetup',
+  'open'
+]);
+
+function registerDeprecatedEventNotifiers(client) {
+  client.on('newListener', eventName => {
+    if (DEPRECATED_UNIFIED_EVENTS.has(eventName)) {
+      emitDeprecationWarning(
+        `The \`${eventName}\` event is no longer supported by the unified topology, please read more by visiting http://bit.ly/2D8WfT6`,
+        'DeprecationWarning'
+      );
+    }
+  });
+}
+
+function createTopology(mongoClient, topologyType, options, callback) {
+  // Pass in the promise library
+  options.promiseLibrary = mongoClient.s.promiseLibrary;
+
+  const translationOptions = {};
+  if (topologyType === 'unified') translationOptions.createServers = false;
+
+  // Set default options
+  const servers = translateOptions(options, translationOptions);
+
+  // determine CSFLE support
+  if (options.autoEncryption != null) {
+    let AutoEncrypter;
+    try {
+      require.resolve('mongodb-client-encryption');
+    } catch (err) {
+      callback(
+        new MongoError(
+          'Auto-encryption requested, but the module is not installed. Please add `mongodb-client-encryption` as a dependency of your project'
+        )
+      );
+      return;
+    }
+
+    try {
+      let mongodbClientEncryption = require('mongodb-client-encryption');
+      if (typeof mongodbClientEncryption.extension !== 'function') {
+        callback(
+          new MongoError(
+            'loaded version of `mongodb-client-encryption` does not have property `extension`. Please make sure you are loading the correct version of `mongodb-client-encryption`'
+          )
+        );
+      }
+      AutoEncrypter = mongodbClientEncryption.extension(require('../../index')).AutoEncrypter;
+    } catch (err) {
+      callback(err);
+      return;
+    }
+
+    const mongoCryptOptions = Object.assign(
+      {
+        bson:
+          options.bson ||
+          new BSON([
+            BSON.Binary,
+            BSON.Code,
+            BSON.DBRef,
+            BSON.Decimal128,
+            BSON.Double,
+            BSON.Int32,
+            BSON.Long,
+            BSON.Map,
+            BSON.MaxKey,
+            BSON.MinKey,
+            BSON.ObjectId,
+            BSON.BSONRegExp,
+            BSON.Symbol,
+            BSON.Timestamp
+          ])
+      },
+      options.autoEncryption
+    );
+
+    options.autoEncrypter = new AutoEncrypter(mongoClient, mongoCryptOptions);
+  }
+
+  // Create the topology
+  let topology;
+  if (topologyType === 'mongos') {
+    topology = new Mongos(servers, options);
+  } else if (topologyType === 'replicaset') {
+    topology = new ReplSet(servers, options);
+  } else if (topologyType === 'unified') {
+    topology = new NativeTopology(options.servers, options);
+    registerDeprecatedEventNotifiers(mongoClient);
+  }
+
+  // Add listeners
+  addListeners(mongoClient, topology);
+
+  // Propagate the events to the client
+  relayEvents(mongoClient, topology);
+
+  // Open the connection
+  assignTopology(mongoClient, topology);
+
+  // initialize CSFLE if requested
+  if (options.autoEncrypter) {
+    options.autoEncrypter.init(err => {
+      if (err) {
+        callback(err);
+        return;
+      }
+
+      topology.connect(options, err => {
+        if (err) {
+          topology.close(true);
+          callback(err);
+          return;
+        }
+
+        callback(undefined, topology);
+      });
+    });
+
+    return;
+  }
+
+  // otherwise connect normally
+  topology.connect(options, err => {
+    if (err) {
+      topology.close(true);
+      return callback(err);
+    }
+
+    callback(undefined, topology);
+    return;
+  });
+}
+
+function createUnifiedOptions(finalOptions, options) {
+  const childOptions = [
+    'mongos',
+    'server',
+    'db',
+    'replset',
+    'db_options',
+    'server_options',
+    'rs_options',
+    'mongos_options'
+  ];
+  const noMerge = ['readconcern', 'compression', 'autoencryption'];
+
+  for (const name in options) {
+    if (noMerge.indexOf(name.toLowerCase()) !== -1) {
+      finalOptions[name] = options[name];
+    } else if (childOptions.indexOf(name.toLowerCase()) !== -1) {
+      finalOptions = mergeOptions(finalOptions, options[name], false);
+    } else {
+      if (
+        options[name] &&
+        typeof options[name] === 'object' &&
+        !Buffer.isBuffer(options[name]) &&
+        !Array.isArray(options[name])
+      ) {
+        finalOptions = mergeOptions(finalOptions, options[name], true);
+      } else {
+        finalOptions[name] = options[name];
+      }
+    }
+  }
+
+  return finalOptions;
+}
+
+function generateCredentials(client, username, password, options) {
+  options = Object.assign({}, options);
+
+  // the default db to authenticate against is 'self'
+  // if authententicate is called from a retry context, it may be another one, like admin
+  const source = options.authSource || options.authdb || options.dbName;
+
+  // authMechanism
+  const authMechanismRaw = options.authMechanism || 'DEFAULT';
+  const authMechanism = authMechanismRaw.toUpperCase();
+  const mechanismProperties = options.authMechanismProperties;
+
+  if (!VALID_AUTH_MECHANISMS.has(authMechanism)) {
+    throw MongoError.create({
+      message: `authentication mechanism ${authMechanismRaw} not supported', options.authMechanism`,
+      driver: true
+    });
+  }
+
+  return new MongoCredentials({
+    mechanism: AUTH_MECHANISM_INTERNAL_MAP[authMechanism],
+    mechanismProperties,
+    source,
+    username,
+    password
+  });
+}
+
+function legacyTransformUrlOptions(object) {
+  return mergeOptions(createUnifiedOptions({}, object), object, false);
+}
+
+function mergeOptions(target, source, flatten) {
+  for (const name in source) {
+    if (source[name] && typeof source[name] === 'object' && flatten) {
+      target = mergeOptions(target, source[name], flatten);
+    } else {
+      target[name] = source[name];
+    }
+  }
+
+  return target;
+}
+
+function relayEvents(mongoClient, topology) {
+  const serverOrCommandEvents = [
+    // APM
+    'commandStarted',
+    'commandSucceeded',
+    'commandFailed',
+
+    // SDAM
+    'serverOpening',
+    'serverClosed',
+    'serverDescriptionChanged',
+    'serverHeartbeatStarted',
+    'serverHeartbeatSucceeded',
+    'serverHeartbeatFailed',
+    'topologyOpening',
+    'topologyClosed',
+    'topologyDescriptionChanged',
+
+    // Legacy
+    'joined',
+    'left',
+    'ping',
+    'ha'
+  ].concat(CMAP_EVENT_NAMES);
+
+  serverOrCommandEvents.forEach(event => {
+    topology.on(event, (object1, object2) => {
+      mongoClient.emit(event, object1, object2);
+    });
+  });
+}
+
+//
+// Replay any events due to single server connection switching to Mongos
+//
+function replayEvents(mongoClient, events) {
+  for (let i = 0; i < events.length; i++) {
+    mongoClient.emit(events[i].event, events[i].object1, events[i].object2);
+  }
+}
+
+function transformUrlOptions(_object) {
+  let object = Object.assign({ servers: _object.hosts }, _object.options);
+  for (let name in object) {
+    const camelCaseName = LEGACY_OPTIONS_MAP[name];
+    if (camelCaseName) {
+      object[camelCaseName] = object[name];
+    }
+  }
+
+  const hasUsername = _object.auth && _object.auth.username;
+  const hasAuthMechanism = _object.options && _object.options.authMechanism;
+  if (hasUsername || hasAuthMechanism) {
+    object.auth = Object.assign({}, _object.auth);
+    if (object.auth.db) {
+      object.authSource = object.authSource || object.auth.db;
+    }
+
+    if (object.auth.username) {
+      object.auth.user = object.auth.username;
+    }
+  }
+
+  if (_object.defaultDatabase) {
+    object.dbName = _object.defaultDatabase;
+  }
+
+  if (object.maxPoolSize) {
+    object.poolSize = object.maxPoolSize;
+  }
+
+  if (object.readConcernLevel) {
+    object.readConcern = new ReadConcern(object.readConcernLevel);
+  }
+
+  if (object.wTimeoutMS) {
+    object.wtimeout = object.wTimeoutMS;
+  }
+
+  if (_object.srvHost) {
+    object.srvHost = _object.srvHost;
+  }
+
+  return object;
+}
+
+function translateOptions(options, translationOptions) {
+  translationOptions = Object.assign({}, { createServers: true }, translationOptions);
+
+  // If we have a readPreference passed in by the db options
+  if (typeof options.readPreference === 'string' || typeof options.read_preference === 'string') {
+    options.readPreference = new ReadPreference(options.readPreference || options.read_preference);
+  }
+
+  // Do we have readPreference tags, add them
+  if (options.readPreference && (options.readPreferenceTags || options.read_preference_tags)) {
+    options.readPreference.tags = options.readPreferenceTags || options.read_preference_tags;
+  }
+
+  // Do we have maxStalenessSeconds
+  if (options.maxStalenessSeconds) {
+    options.readPreference.maxStalenessSeconds = options.maxStalenessSeconds;
+  }
+
+  // Set the socket and connection timeouts
+  if (options.socketTimeoutMS == null) options.socketTimeoutMS = 0;
+  if (options.connectTimeoutMS == null) options.connectTimeoutMS = 10000;
+
+  if (!translationOptions.createServers) {
+    return;
+  }
+
+  // Create server instances
+  return options.servers.map(serverObj => {
+    return serverObj.domain_socket
+      ? new Server(serverObj.domain_socket, 27017, options)
+      : new Server(serverObj.host, serverObj.port, options);
+  });
+}
+
+module.exports = { validOptions, connect };
diff --git a/node_modules/mongodb/lib/operations/count.js b/node_modules/mongodb/lib/operations/count.js
new file mode 100644
index 0000000..a7216d6
--- /dev/null
+++ b/node_modules/mongodb/lib/operations/count.js
@@ -0,0 +1,68 @@
+'use strict';
+
+const buildCountCommand = require('./common_functions').buildCountCommand;
+const OperationBase = require('./operation').OperationBase;
+
+class CountOperation extends OperationBase {
+  constructor(cursor, applySkipLimit, options) {
+    super(options);
+
+    this.cursor = cursor;
+    this.applySkipLimit = applySkipLimit;
+  }
+
+  execute(callback) {
+    const cursor = this.cursor;
+    const applySkipLimit = this.applySkipLimit;
+    const options = this.options;
+
+    if (applySkipLimit) {
+      if (typeof cursor.cursorSkip() === 'number') options.skip = cursor.cursorSkip();
+      if (typeof cursor.cursorLimit() === 'number') options.limit = cursor.cursorLimit();
+    }
+
+    // Ensure we have the right read preference inheritance
+    if (options.readPreference) {
+      cursor.setReadPreference(options.readPreference);
+    }
+
+    if (
+      typeof options.maxTimeMS !== 'number' &&
+      cursor.cmd &&
+      typeof cursor.cmd.maxTimeMS === 'number'
+    ) {
+      options.maxTimeMS = cursor.cmd.maxTimeMS;
+    }
+
+    let finalOptions = {};
+    finalOptions.skip = options.skip;
+    finalOptions.limit = options.limit;
+    finalOptions.hint = options.hint;
+    finalOptions.maxTimeMS = options.maxTimeMS;
+
+    // Command
+    finalOptions.collectionName = cursor.namespace.collection;
+
+    let command;
+    try {
+      command = buildCountCommand(cursor, cursor.cmd.query, finalOptions);
+    } catch (err) {
+      return callback(err);
+    }
+
+    // Set cursor server to the same as the topology
+    cursor.server = cursor.topology.s.coreTopology;
+
+    // Execute the command
+    cursor.topology.command(
+      cursor.namespace.withCollection('$cmd'),
+      command,
+      cursor.options,
+      (err, result) => {
+        callback(err, result ? result.result.n : null);
+      }
+    );
+  }
+}
+
+module.exports = CountOperation;
diff --git a/node_modules/mongodb/lib/operations/count_documents.js b/node_modules/mongodb/lib/operations/count_documents.js
new file mode 100644
index 0000000..d043abf
--- /dev/null
+++ b/node_modules/mongodb/lib/operations/count_documents.js
@@ -0,0 +1,41 @@
+'use strict';
+
+const AggregateOperation = require('./aggregate');
+
+class CountDocumentsOperation extends AggregateOperation {
+  constructor(collection, query, options) {
+    const pipeline = [{ $match: query }];
+    if (typeof options.skip === 'number') {
+      pipeline.push({ $skip: options.skip });
+    }
+
+    if (typeof options.limit === 'number') {
+      pipeline.push({ $limit: options.limit });
+    }
+
+    pipeline.push({ $group: { _id: 1, n: { $sum: 1 } } });
+
+    super(collection, pipeline, options);
+  }
+
+  execute(server, callback) {
+    super.execute(server, (err, result) => {
+      if (err) {
+        callback(err, null);
+        return;
+      }
+
+      // NOTE: We're avoiding creating a cursor here to reduce the callstack.
+      const response = result.result;
+      if (response.cursor == null || response.cursor.firstBatch == null) {
+        callback(null, 0);
+        return;
+      }
+
+      const docs = response.cursor.firstBatch;
+      callback(null, docs.length ? docs[0].n : 0);
+    });
+  }
+}
+
+module.exports = CountDocumentsOperation;
diff --git a/node_modules/mongodb/lib/operations/create_collection.js b/node_modules/mongodb/lib/operations/create_collection.js
new file mode 100644
index 0000000..c84adb0
--- /dev/null
+++ b/node_modules/mongodb/lib/operations/create_collection.js
@@ -0,0 +1,102 @@
+'use strict';
+
+const Aspect = require('./operation').Aspect;
+const defineAspects = require('./operation').defineAspects;
+const CommandOperation = require('./command');
+const applyWriteConcern = require('../utils').applyWriteConcern;
+const loadCollection = require('../dynamic_loaders').loadCollection;
+const MongoError = require('../core').MongoError;
+const ReadPreference = require('../core').ReadPreference;
+
+const ILLEGAL_COMMAND_FIELDS = new Set([
+  'w',
+  'wtimeout',
+  'j',
+  'fsync',
+  'autoIndexId',
+  'strict',
+  'serializeFunctions',
+  'pkFactory',
+  'raw',
+  'readPreference',
+  'session',
+  'readConcern',
+  'writeConcern'
+]);
+
+class CreateCollectionOperation extends CommandOperation {
+  constructor(db, name, options) {
+    super(db, options);
+    this.name = name;
+  }
+
+  _buildCommand() {
+    const name = this.name;
+    const options = this.options;
+
+    const cmd = { create: name };
+    for (let n in options) {
+      if (
+        options[n] != null &&
+        typeof options[n] !== 'function' &&
+        !ILLEGAL_COMMAND_FIELDS.has(n)
+      ) {
+        cmd[n] = options[n];
+      }
+    }
+
+    return cmd;
+  }
+
+  execute(callback) {
+    const db = this.db;
+    const name = this.name;
+    const options = this.options;
+    const Collection = loadCollection();
+
+    let listCollectionOptions = Object.assign({ nameOnly: true, strict: false }, options);
+    listCollectionOptions = applyWriteConcern(listCollectionOptions, { db }, listCollectionOptions);
+
+    function done(err) {
+      if (err) {
+        return callback(err);
+      }
+
+      try {
+        callback(
+          null,
+          new Collection(db, db.s.topology, db.databaseName, name, db.s.pkFactory, options)
+        );
+      } catch (err) {
+        callback(err);
+      }
+    }
+
+    const strictMode = listCollectionOptions.strict;
+    if (strictMode) {
+      db.listCollections({ name }, listCollectionOptions)
+        .setReadPreference(ReadPreference.PRIMARY)
+        .toArray((err, collections) => {
+          if (err) {
+            return callback(err);
+          }
+
+          if (collections.length > 0) {
+            return callback(
+              new MongoError(`Collection ${name} already exists. Currently in strict mode.`)
+            );
+          }
+
+          super.execute(done);
+        });
+
+      return;
+    }
+
+    // otherwise just execute the command
+    super.execute(done);
+  }
+}
+
+defineAspects(CreateCollectionOperation, Aspect.WRITE_OPERATION);
+module.exports = CreateCollectionOperation;
diff --git a/node_modules/mongodb/lib/operations/create_indexes.js b/node_modules/mongodb/lib/operations/create_indexes.js
new file mode 100644
index 0000000..211b43c
--- /dev/null
+++ b/node_modules/mongodb/lib/operations/create_indexes.js
@@ -0,0 +1,137 @@
+'use strict';
+
+const Aspect = require('./operation').Aspect;
+const defineAspects = require('./operation').defineAspects;
+const CommandOperationV2 = require('./command_v2');
+const MongoError = require('../core').MongoError;
+const parseIndexOptions = require('../utils').parseIndexOptions;
+const maxWireVersion = require('../core/utils').maxWireVersion;
+
+const VALID_INDEX_OPTIONS = new Set([
+  'background',
+  'unique',
+  'name',
+  'partialFilterExpression',
+  'sparse',
+  'expireAfterSeconds',
+  'storageEngine',
+  'collation',
+
+  // text indexes
+  'weights',
+  'default_language',
+  'language_override',
+  'textIndexVersion',
+
+  // 2d-sphere indexes
+  '2dsphereIndexVersion',
+
+  // 2d indexes
+  'bits',
+  'min',
+  'max',
+
+  // geoHaystack Indexes
+  'bucketSize',
+
+  // wildcard indexes
+  'wildcardProjection'
+]);
+
+class CreateIndexesOperation extends CommandOperationV2 {
+  /**
+   * @ignore
+   */
+  constructor(parent, collection, indexes, options) {
+    super(parent, options);
+    this.collection = collection;
+
+    // createIndex can be called with a variety of styles:
+    //   coll.createIndex('a');
+    //   coll.createIndex({ a: 1 });
+    //   coll.createIndex([['a', 1]]);
+    // createIndexes is always called with an array of index spec objects
+    if (!Array.isArray(indexes) || Array.isArray(indexes[0])) {
+      this.onlyReturnNameOfCreatedIndex = true;
+      // TODO: remove in v4 (breaking change); make createIndex return full response as createIndexes does
+
+      const indexParameters = parseIndexOptions(indexes);
+      // Generate the index name
+      const name = typeof options.name === 'string' ? options.name : indexParameters.name;
+      // Set up the index
+      const indexSpec = { name, key: indexParameters.fieldHash };
+      // merge valid index options into the index spec
+      for (let optionName in options) {
+        if (VALID_INDEX_OPTIONS.has(optionName)) {
+          indexSpec[optionName] = options[optionName];
+        }
+      }
+      this.indexes = [indexSpec];
+      return;
+    }
+
+    this.indexes = indexes;
+  }
+
+  /**
+   * @ignore
+   */
+  execute(server, callback) {
+    const options = this.options;
+    const indexes = this.indexes;
+
+    const serverWireVersion = maxWireVersion(server);
+
+    // Ensure we generate the correct name if the parameter is not set
+    for (let i = 0; i < indexes.length; i++) {
+      // Did the user pass in a collation, check if our write server supports it
+      if (indexes[i].collation && serverWireVersion < 5) {
+        callback(
+          new MongoError(
+            `Server ${server.name}, which reports wire version ${serverWireVersion}, does not support collation`
+          )
+        );
+        return;
+      }
+
+      if (indexes[i].name == null) {
+        const keys = [];
+
+        for (let name in indexes[i].key) {
+          keys.push(`${name}_${indexes[i].key[name]}`);
+        }
+
+        // Set the name
+        indexes[i].name = keys.join('_');
+      }
+    }
+
+    const cmd = { createIndexes: this.collection, indexes };
+
+    if (options.commitQuorum != null) {
+      if (serverWireVersion < 9) {
+        callback(
+          new MongoError('`commitQuorum` option for `createIndexes` not supported on servers < 4.4')
+        );
+        return;
+      }
+      cmd.commitQuorum = options.commitQuorum;
+    }
+
+    // collation is set on each index, it should not be defined at the root
+    this.options.collation = undefined;
+
+    super.executeCommand(server, cmd, (err, result) => {
+      if (err) {
+        callback(err);
+        return;
+      }
+
+      callback(null, this.onlyReturnNameOfCreatedIndex ? indexes[0].name : result);
+    });
+  }
+}
+
+defineAspects(CreateIndexesOperation, [Aspect.WRITE_OPERATION, Aspect.EXECUTE_WITH_SELECTION]);
+
+module.exports = CreateIndexesOperation;
diff --git a/node_modules/mongodb/lib/operations/cursor_ops.js b/node_modules/mongodb/lib/operations/cursor_ops.js
new file mode 100644
index 0000000..fda4c91
--- /dev/null
+++ b/node_modules/mongodb/lib/operations/cursor_ops.js
@@ -0,0 +1,167 @@
+'use strict';
+
+const buildCountCommand = require('./collection_ops').buildCountCommand;
+const handleCallback = require('../utils').handleCallback;
+const MongoError = require('../core').MongoError;
+const push = Array.prototype.push;
+const CursorState = require('../core/cursor').CursorState;
+
+/**
+ * Get the count of documents for this cursor.
+ *
+ * @method
+ * @param {Cursor} cursor The Cursor instance on which to count.
+ * @param {boolean} [applySkipLimit=true] Specifies whether the count command apply limit and skip settings should be applied on the cursor or in the provided options.
+ * @param {object} [options] Optional settings. See Cursor.prototype.count for a list of options.
+ * @param {Cursor~countResultCallback} [callback] The result callback.
+ */
+function count(cursor, applySkipLimit, opts, callback) {
+  if (applySkipLimit) {
+    if (typeof cursor.cursorSkip() === 'number') opts.skip = cursor.cursorSkip();
+    if (typeof cursor.cursorLimit() === 'number') opts.limit = cursor.cursorLimit();
+  }
+
+  // Ensure we have the right read preference inheritance
+  if (opts.readPreference) {
+    cursor.setReadPreference(opts.readPreference);
+  }
+
+  if (
+    typeof opts.maxTimeMS !== 'number' &&
+    cursor.cmd &&
+    typeof cursor.cmd.maxTimeMS === 'number'
+  ) {
+    opts.maxTimeMS = cursor.cmd.maxTimeMS;
+  }
+
+  let options = {};
+  options.skip = opts.skip;
+  options.limit = opts.limit;
+  options.hint = opts.hint;
+  options.maxTimeMS = opts.maxTimeMS;
+
+  // Command
+  options.collectionName = cursor.namespace.collection;
+
+  let command;
+  try {
+    command = buildCountCommand(cursor, cursor.cmd.query, options);
+  } catch (err) {
+    return callback(err);
+  }
+
+  // Set cursor server to the same as the topology
+  cursor.server = cursor.topology.s.coreTopology;
+
+  // Execute the command
+  cursor.topology.command(
+    cursor.namespace.withCollection('$cmd'),
+    command,
+    cursor.options,
+    (err, result) => {
+      callback(err, result ? result.result.n : null);
+    }
+  );
+}
+
+/**
+ * Iterates over all the documents for this cursor. See Cursor.prototype.each for more information.
+ *
+ * @method
+ * @deprecated
+ * @param {Cursor} cursor The Cursor instance on which to run.
+ * @param {Cursor~resultCallback} callback The result callback.
+ */
+function each(cursor, callback) {
+  if (!callback) throw MongoError.create({ message: 'callback is mandatory', driver: true });
+  if (cursor.isNotified()) return;
+  if (cursor.s.state === CursorState.CLOSED || cursor.isDead()) {
+    return handleCallback(
+      callback,
+      MongoError.create({ message: 'Cursor is closed', driver: true })
+    );
+  }
+
+  if (cursor.s.state === CursorState.INIT) {
+    cursor.s.state = CursorState.OPEN;
+  }
+
+  // Define function to avoid global scope escape
+  let fn = null;
+  // Trampoline all the entries
+  if (cursor.bufferedCount() > 0) {
+    while ((fn = loop(cursor, callback))) fn(cursor, callback);
+    each(cursor, callback);
+  } else {
+    cursor.next((err, item) => {
+      if (err) return handleCallback(callback, err);
+      if (item == null) {
+        return cursor.close({ skipKillCursors: true }, () => handleCallback(callback, null, null));
+      }
+
+      if (handleCallback(callback, null, item) === false) return;
+      each(cursor, callback);
+    });
+  }
+}
+
+// Trampoline emptying the number of retrieved items
+// without incurring a nextTick operation
+function loop(cursor, callback) {
+  // No more items we are done
+  if (cursor.bufferedCount() === 0) return;
+  // Get the next document
+  cursor._next(callback);
+  // Loop
+  return loop;
+}
+
+/**
+ * Returns an array of documents. See Cursor.prototype.toArray for more information.
+ *
+ * @method
+ * @param {Cursor} cursor The Cursor instance from which to get the next document.
+ * @param {Cursor~toArrayResultCallback} [callback] The result callback.
+ */
+function toArray(cursor, callback) {
+  const items = [];
+
+  // Reset cursor
+  cursor.rewind();
+  cursor.s.state = CursorState.INIT;
+
+  // Fetch all the documents
+  const fetchDocs = () => {
+    cursor._next((err, doc) => {
+      if (err) {
+        return handleCallback(callback, err);
+      }
+
+      if (doc == null) {
+        return cursor.close({ skipKillCursors: true }, () => handleCallback(callback, null, items));
+      }
+
+      // Add doc to items
+      items.push(doc);
+
+      // Get all buffered objects
+      if (cursor.bufferedCount() > 0) {
+        let docs = cursor.readBufferedDocuments(cursor.bufferedCount());
+
+        // Transform the doc if transform method added
+        if (cursor.s.transforms && typeof cursor.s.transforms.doc === 'function') {
+          docs = docs.map(cursor.s.transforms.doc);
+        }
+
+        push.apply(items, docs);
+      }
+
+      // Attempt a fetch
+      fetchDocs();
+    });
+  };
+
+  fetchDocs();
+}
+
+module.exports = { count, each, toArray };
diff --git a/node_modules/mongodb/lib/operations/db_ops.js b/node_modules/mongodb/lib/operations/db_ops.js
new file mode 100644
index 0000000..8f9b890
--- /dev/null
+++ b/node_modules/mongodb/lib/operations/db_ops.js
@@ -0,0 +1,467 @@
+'use strict';
+
+const applyWriteConcern = require('../utils').applyWriteConcern;
+const Code = require('../core').BSON.Code;
+const debugOptions = require('../utils').debugOptions;
+const handleCallback = require('../utils').handleCallback;
+const MongoError = require('../core').MongoError;
+const parseIndexOptions = require('../utils').parseIndexOptions;
+const ReadPreference = require('../core').ReadPreference;
+const toError = require('../utils').toError;
+const CONSTANTS = require('../constants');
+const MongoDBNamespace = require('../utils').MongoDBNamespace;
+
+const debugFields = [
+  'authSource',
+  'w',
+  'wtimeout',
+  'j',
+  'native_parser',
+  'forceServerObjectId',
+  'serializeFunctions',
+  'raw',
+  'promoteLongs',
+  'promoteValues',
+  'promoteBuffers',
+  'bufferMaxEntries',
+  'numberOfRetries',
+  'retryMiliSeconds',
+  'readPreference',
+  'pkFactory',
+  'parentDb',
+  'promiseLibrary',
+  'noListener'
+];
+
+/**
+ * Creates an index on the db and collection.
+ * @method
+ * @param {Db} db The Db instance on which to create an index.
+ * @param {string} name Name of the collection to create the index on.
+ * @param {(string|object)} fieldOrSpec Defines the index.
+ * @param {object} [options] Optional settings. See Db.prototype.createIndex for a list of options.
+ * @param {Db~resultCallback} [callback] The command result callback
+ */
+function createIndex(db, name, fieldOrSpec, options, callback) {
+  // Get the write concern options
+  let finalOptions = Object.assign({}, { readPreference: ReadPreference.PRIMARY }, options);
+  finalOptions = applyWriteConcern(finalOptions, { db }, options);
+
+  // Ensure we have a callback
+  if (finalOptions.writeConcern && typeof callback !== 'function') {
+    throw MongoError.create({
+      message: 'Cannot use a writeConcern without a provided callback',
+      driver: true
+    });
+  }
+
+  // Did the user destroy the topology
+  if (db.serverConfig && db.serverConfig.isDestroyed())
+    return callback(new MongoError('topology was destroyed'));
+
+  // Attempt to run using createIndexes command
+  createIndexUsingCreateIndexes(db, name, fieldOrSpec, finalOptions, (err, result) => {
+    if (err == null) return handleCallback(callback, err, result);
+
+    /**
+     * The following errors mean that the server recognized `createIndex` as a command so we don't need to fallback to an insert:
+     * 67 = 'CannotCreateIndex' (malformed index options)
+     * 85 = 'IndexOptionsConflict' (index already exists with different options)
+     * 86 = 'IndexKeySpecsConflict' (index already exists with the same name)
+     * 11000 = 'DuplicateKey' (couldn't build unique index because of dupes)
+     * 11600 = 'InterruptedAtShutdown' (interrupted at shutdown)
+     * 197 = 'InvalidIndexSpecificationOption' (`_id` with `background: true`)
+     */
+    if (
+      err.code === 67 ||
+      err.code === 11000 ||
+      err.code === 85 ||
+      err.code === 86 ||
+      err.code === 11600 ||
+      err.code === 197
+    ) {
+      return handleCallback(callback, err, result);
+    }
+
+    // Create command
+    const doc = createCreateIndexCommand(db, name, fieldOrSpec, options);
+    // Set no key checking
+    finalOptions.checkKeys = false;
+    // Insert document
+    db.s.topology.insert(
+      db.s.namespace.withCollection(CONSTANTS.SYSTEM_INDEX_COLLECTION),
+      doc,
+      finalOptions,
+      (err, result) => {
+        if (callback == null) return;
+        if (err) return handleCallback(callback, err);
+        if (result == null) return handleCallback(callback, null, null);
+        if (result.result.writeErrors)
+          return handleCallback(callback, MongoError.create(result.result.writeErrors[0]), null);
+        handleCallback(callback, null, doc.name);
+      }
+    );
+  });
+}
+
+// Add listeners to topology
+function createListener(db, e, object) {
+  function listener(err) {
+    if (object.listeners(e).length > 0) {
+      object.emit(e, err, db);
+
+      // Emit on all associated db's if available
+      for (let i = 0; i < db.s.children.length; i++) {
+        db.s.children[i].emit(e, err, db.s.children[i]);
+      }
+    }
+  }
+  return listener;
+}
+
+/**
+ * Ensures that an index exists. If it does not, creates it.
+ *
+ * @method
+ * @param {Db} db The Db instance on which to ensure the index.
+ * @param {string} name The index name
+ * @param {(string|object)} fieldOrSpec Defines the index.
+ * @param {object} [options] Optional settings. See Db.prototype.ensureIndex for a list of options.
+ * @param {Db~resultCallback} [callback] The command result callback
+ */
+function ensureIndex(db, name, fieldOrSpec, options, callback) {
+  // Get the write concern options
+  const finalOptions = applyWriteConcern({}, { db }, options);
+  // Create command
+  const selector = createCreateIndexCommand(db, name, fieldOrSpec, options);
+  const index_name = selector.name;
+
+  // Did the user destroy the topology
+  if (db.serverConfig && db.serverConfig.isDestroyed())
+    return callback(new MongoError('topology was destroyed'));
+
+  // Merge primary readPreference
+  finalOptions.readPreference = ReadPreference.PRIMARY;
+
+  // Check if the index already exists
+  indexInformation(db, name, finalOptions, (err, indexInformation) => {
+    if (err != null && err.code !== 26) return handleCallback(callback, err, null);
+    // If the index does not exist, create it
+    if (indexInformation == null || !indexInformation[index_name]) {
+      createIndex(db, name, fieldOrSpec, options, callback);
+    } else {
+      if (typeof callback === 'function') return handleCallback(callback, null, index_name);
+    }
+  });
+}
+
+/**
+ * Evaluate JavaScript on the server
+ *
+ * @method
+ * @param {Db} db The Db instance.
+ * @param {Code} code JavaScript to execute on server.
+ * @param {(object|array)} parameters The parameters for the call.
+ * @param {object} [options] Optional settings. See Db.prototype.eval for a list of options.
+ * @param {Db~resultCallback} [callback] The results callback
+ * @deprecated Eval is deprecated on MongoDB 3.2 and forward
+ */
+function evaluate(db, code, parameters, options, callback) {
+  let finalCode = code;
+  let finalParameters = [];
+
+  // Did the user destroy the topology
+  if (db.serverConfig && db.serverConfig.isDestroyed())
+    return callback(new MongoError('topology was destroyed'));
+
+  // If not a code object translate to one
+  if (!(finalCode && finalCode._bsontype === 'Code')) finalCode = new Code(finalCode);
+  // Ensure the parameters are correct
+  if (parameters != null && !Array.isArray(parameters) && typeof parameters !== 'function') {
+    finalParameters = [parameters];
+  } else if (parameters != null && Array.isArray(parameters) && typeof parameters !== 'function') {
+    finalParameters = parameters;
+  }
+
+  // Create execution selector
+  let cmd = { $eval: finalCode, args: finalParameters };
+  // Check if the nolock parameter is passed in
+  if (options['nolock']) {
+    cmd['nolock'] = options['nolock'];
+  }
+
+  // Set primary read preference
+  options.readPreference = new ReadPreference(ReadPreference.PRIMARY);
+
+  // Execute the command
+  executeCommand(db, cmd, options, (err, result) => {
+    if (err) return handleCallback(callback, err, null);
+    if (result && result.ok === 1) return handleCallback(callback, null, result.retval);
+    if (result)
+      return handleCallback(
+        callback,
+        MongoError.create({ message: `eval failed: ${result.errmsg}`, driver: true }),
+        null
+      );
+    handleCallback(callback, err, result);
+  });
+}
+
+/**
+ * Execute a command
+ *
+ * @method
+ * @param {Db} db The Db instance on which to execute the command.
+ * @param {object} command The command hash
+ * @param {object} [options] Optional settings. See Db.prototype.command for a list of options.
+ * @param {Db~resultCallback} [callback] The command result callback
+ */
+function executeCommand(db, command, options, callback) {
+  // Did the user destroy the topology
+  if (db.serverConfig && db.serverConfig.isDestroyed())
+    return callback(new MongoError('topology was destroyed'));
+  // Get the db name we are executing against
+  const dbName = options.dbName || options.authdb || db.databaseName;
+
+  // Convert the readPreference if its not a write
+  options.readPreference = ReadPreference.resolve(db, options);
+
+  // Debug information
+  if (db.s.logger.isDebug())
+    db.s.logger.debug(
+      `executing command ${JSON.stringify(
+        command
+      )} against ${dbName}.$cmd with options [${JSON.stringify(
+        debugOptions(debugFields, options)
+      )}]`
+    );
+
+  // Execute command
+  db.s.topology.command(db.s.namespace.withCollection('$cmd'), command, options, (err, result) => {
+    if (err) return handleCallback(callback, err);
+    if (options.full) return handleCallback(callback, null, result);
+    handleCallback(callback, null, result.result);
+  });
+}
+
+/**
+ * Runs a command on the database as admin.
+ *
+ * @method
+ * @param {Db} db The Db instance on which to execute the command.
+ * @param {object} command The command hash
+ * @param {object} [options] Optional settings. See Db.prototype.executeDbAdminCommand for a list of options.
+ * @param {Db~resultCallback} [callback] The command result callback
+ */
+function executeDbAdminCommand(db, command, options, callback) {
+  const namespace = new MongoDBNamespace('admin', '$cmd');
+
+  db.s.topology.command(namespace, command, options, (err, result) => {
+    // Did the user destroy the topology
+    if (db.serverConfig && db.serverConfig.isDestroyed()) {
+      return callback(new MongoError('topology was destroyed'));
+    }
+
+    if (err) return handleCallback(callback, err);
+    handleCallback(callback, null, result.result);
+  });
+}
+
+/**
+ * Retrieves this collections index info.
+ *
+ * @method
+ * @param {Db} db The Db instance on which to retrieve the index info.
+ * @param {string} name The name of the collection.
+ * @param {object} [options] Optional settings. See Db.prototype.indexInformation for a list of options.
+ * @param {Db~resultCallback} [callback] The command result callback
+ */
+function indexInformation(db, name, options, callback) {
+  // If we specified full information
+  const full = options['full'] == null ? false : options['full'];
+
+  // Did the user destroy the topology
+  if (db.serverConfig && db.serverConfig.isDestroyed())
+    return callback(new MongoError('topology was destroyed'));
+  // Process all the results from the index command and collection
+  function processResults(indexes) {
+    // Contains all the information
+    let info = {};
+    // Process all the indexes
+    for (let i = 0; i < indexes.length; i++) {
+      const index = indexes[i];
+      // Let's unpack the object
+      info[index.name] = [];
+      for (let name in index.key) {
+        info[index.name].push([name, index.key[name]]);
+      }
+    }
+
+    return info;
+  }
+
+  // Get the list of indexes of the specified collection
+  db.collection(name)
+    .listIndexes(options)
+    .toArray((err, indexes) => {
+      if (err) return callback(toError(err));
+      if (!Array.isArray(indexes)) return handleCallback(callback, null, []);
+      if (full) return handleCallback(callback, null, indexes);
+      handleCallback(callback, null, processResults(indexes));
+    });
+}
+
+/**
+ * Retrieve the current profiling information for MongoDB
+ *
+ * @method
+ * @param {Db} db The Db instance on which to retrieve the profiling info.
+ * @param {Object} [options] Optional settings. See Db.protoype.profilingInfo for a list of options.
+ * @param {Db~resultCallback} [callback] The command result callback.
+ * @deprecated Query the system.profile collection directly.
+ */
+function profilingInfo(db, options, callback) {
+  try {
+    db.collection('system.profile')
+      .find({}, options)
+      .toArray(callback);
+  } catch (err) {
+    return callback(err, null);
+  }
+}
+
+// Validate the database name
+function validateDatabaseName(databaseName) {
+  if (typeof databaseName !== 'string')
+    throw MongoError.create({ message: 'database name must be a string', driver: true });
+  if (databaseName.length === 0)
+    throw MongoError.create({ message: 'database name cannot be the empty string', driver: true });
+  if (databaseName === '$external') return;
+
+  const invalidChars = [' ', '.', '$', '/', '\\'];
+  for (let i = 0; i < invalidChars.length; i++) {
+    if (databaseName.indexOf(invalidChars[i]) !== -1)
+      throw MongoError.create({
+        message: "database names cannot contain the character '" + invalidChars[i] + "'",
+        driver: true
+      });
+  }
+}
+
+/**
+ * Create the command object for Db.prototype.createIndex.
+ *
+ * @param {Db} db The Db instance on which to create the command.
+ * @param {string} name Name of the collection to create the index on.
+ * @param {(string|object)} fieldOrSpec Defines the index.
+ * @param {Object} [options] Optional settings. See Db.prototype.createIndex for a list of options.
+ * @return {Object} The insert command object.
+ */
+function createCreateIndexCommand(db, name, fieldOrSpec, options) {
+  const indexParameters = parseIndexOptions(fieldOrSpec);
+  const fieldHash = indexParameters.fieldHash;
+
+  // Generate the index name
+  const indexName = typeof options.name === 'string' ? options.name : indexParameters.name;
+  const selector = {
+    ns: db.s.namespace.withCollection(name).toString(),
+    key: fieldHash,
+    name: indexName
+  };
+
+  // Ensure we have a correct finalUnique
+  const finalUnique = options == null || 'object' === typeof options ? false : options;
+  // Set up options
+  options = options == null || typeof options === 'boolean' ? {} : options;
+
+  // Add all the options
+  const keysToOmit = Object.keys(selector);
+  for (let optionName in options) {
+    if (keysToOmit.indexOf(optionName) === -1) {
+      selector[optionName] = options[optionName];
+    }
+  }
+
+  if (selector['unique'] == null) selector['unique'] = finalUnique;
+
+  // Remove any write concern operations
+  const removeKeys = ['w', 'wtimeout', 'j', 'fsync', 'readPreference', 'session'];
+  for (let i = 0; i < removeKeys.length; i++) {
+    delete selector[removeKeys[i]];
+  }
+
+  // Return the command creation selector
+  return selector;
+}
+
+/**
+ * Create index using the createIndexes command.
+ *
+ * @param {Db} db The Db instance on which to execute the command.
+ * @param {string} name Name of the collection to create the index on.
+ * @param {(string|object)} fieldOrSpec Defines the index.
+ * @param {Object} [options] Optional settings. See Db.prototype.createIndex for a list of options.
+ * @param {Db~resultCallback} [callback] The command result callback.
+ */
+function createIndexUsingCreateIndexes(db, name, fieldOrSpec, options, callback) {
+  // Build the index
+  const indexParameters = parseIndexOptions(fieldOrSpec);
+  // Generate the index name
+  const indexName = typeof options.name === 'string' ? options.name : indexParameters.name;
+  // Set up the index
+  const indexes = [{ name: indexName, key: indexParameters.fieldHash }];
+  // merge all the options
+  const keysToOmit = Object.keys(indexes[0]).concat([
+    'writeConcern',
+    'w',
+    'wtimeout',
+    'j',
+    'fsync',
+    'readPreference',
+    'session'
+  ]);
+
+  for (let optionName in options) {
+    if (keysToOmit.indexOf(optionName) === -1) {
+      indexes[0][optionName] = options[optionName];
+    }
+  }
+
+  // Get capabilities
+  const capabilities = db.s.topology.capabilities();
+
+  // Did the user pass in a collation, check if our write server supports it
+  if (indexes[0].collation && capabilities && !capabilities.commandsTakeCollation) {
+    // Create a new error
+    const error = new MongoError('server/primary/mongos does not support collation');
+    error.code = 67;
+    // Return the error
+    return callback(error);
+  }
+
+  // Create command, apply write concern to command
+  const cmd = applyWriteConcern({ createIndexes: name, indexes }, { db }, options);
+
+  // ReadPreference primary
+  options.readPreference = ReadPreference.PRIMARY;
+
+  // Build the command
+  executeCommand(db, cmd, options, (err, result) => {
+    if (err) return handleCallback(callback, err, null);
+    if (result.ok === 0) return handleCallback(callback, toError(result), null);
+    // Return the indexName for backward compatibility
+    handleCallback(callback, null, indexName);
+  });
+}
+
+module.exports = {
+  createListener,
+  createIndex,
+  ensureIndex,
+  evaluate,
+  executeCommand,
+  executeDbAdminCommand,
+  indexInformation,
+  profilingInfo,
+  validateDatabaseName
+};
diff --git a/node_modules/mongodb/lib/operations/delete_many.js b/node_modules/mongodb/lib/operations/delete_many.js
new file mode 100644
index 0000000..d881f67
--- /dev/null
+++ b/node_modules/mongodb/lib/operations/delete_many.js
@@ -0,0 +1,25 @@
+'use strict';
+
+const OperationBase = require('./operation').OperationBase;
+const deleteCallback = require('./common_functions').deleteCallback;
+const removeDocuments = require('./common_functions').removeDocuments;
+
+class DeleteManyOperation extends OperationBase {
+  constructor(collection, filter, options) {
+    super(options);
+
+    this.collection = collection;
+    this.filter = filter;
+  }
+
+  execute(callback) {
+    const coll = this.collection;
+    const filter = this.filter;
+    const options = this.options;
+
+    options.single = false;
+    removeDocuments(coll, filter, options, (err, r) => deleteCallback(err, r, callback));
+  }
+}
+
+module.exports = DeleteManyOperation;
diff --git a/node_modules/mongodb/lib/operations/delete_one.js b/node_modules/mongodb/lib/operations/delete_one.js
new file mode 100644
index 0000000..b05597f
--- /dev/null
+++ b/node_modules/mongodb/lib/operations/delete_one.js
@@ -0,0 +1,25 @@
+'use strict';
+
+const OperationBase = require('./operation').OperationBase;
+const deleteCallback = require('./common_functions').deleteCallback;
+const removeDocuments = require('./common_functions').removeDocuments;
+
+class DeleteOneOperation extends OperationBase {
+  constructor(collection, filter, options) {
+    super(options);
+
+    this.collection = collection;
+    this.filter = filter;
+  }
+
+  execute(callback) {
+    const coll = this.collection;
+    const filter = this.filter;
+    const options = this.options;
+
+    options.single = true;
+    removeDocuments(coll, filter, options, (err, r) => deleteCallback(err, r, callback));
+  }
+}
+
+module.exports = DeleteOneOperation;
diff --git a/node_modules/mongodb/lib/operations/distinct.js b/node_modules/mongodb/lib/operations/distinct.js
new file mode 100644
index 0000000..dcf4f7e
--- /dev/null
+++ b/node_modules/mongodb/lib/operations/distinct.js
@@ -0,0 +1,85 @@
+'use strict';
+
+const Aspect = require('./operation').Aspect;
+const defineAspects = require('./operation').defineAspects;
+const CommandOperationV2 = require('./command_v2');
+const decorateWithCollation = require('../utils').decorateWithCollation;
+const decorateWithReadConcern = require('../utils').decorateWithReadConcern;
+
+/**
+ * Return a list of distinct values for the given key across a collection.
+ *
+ * @class
+ * @property {Collection} a Collection instance.
+ * @property {string} key Field of the document to find distinct values for.
+ * @property {object} query The query for filtering the set of documents to which we apply the distinct filter.
+ * @property {object} [options] Optional settings. See Collection.prototype.distinct for a list of options.
+ */
+class DistinctOperation extends CommandOperationV2 {
+  /**
+   * Construct a Distinct operation.
+   *
+   * @param {Collection} a Collection instance.
+   * @param {string} key Field of the document to find distinct values for.
+   * @param {object} query The query for filtering the set of documents to which we apply the distinct filter.
+   * @param {object} [options] Optional settings. See Collection.prototype.distinct for a list of options.
+   */
+  constructor(collection, key, query, options) {
+    super(collection, options);
+
+    this.collection = collection;
+    this.key = key;
+    this.query = query;
+  }
+
+  /**
+   * Execute the operation.
+   *
+   * @param {Collection~resultCallback} [callback] The command result callback
+   */
+  execute(server, callback) {
+    const coll = this.collection;
+    const key = this.key;
+    const query = this.query;
+    const options = this.options;
+
+    // Distinct command
+    const cmd = {
+      distinct: coll.collectionName,
+      key: key,
+      query: query
+    };
+
+    // Add maxTimeMS if defined
+    if (typeof options.maxTimeMS === 'number') {
+      cmd.maxTimeMS = options.maxTimeMS;
+    }
+
+    // Do we have a readConcern specified
+    decorateWithReadConcern(cmd, coll, options);
+
+    // Have we specified collation
+    try {
+      decorateWithCollation(cmd, coll, options);
+    } catch (err) {
+      return callback(err, null);
+    }
+
+    super.executeCommand(server, cmd, (err, result) => {
+      if (err) {
+        callback(err);
+        return;
+      }
+
+      callback(null, this.options.full ? result : result.values);
+    });
+  }
+}
+
+defineAspects(DistinctOperation, [
+  Aspect.READ_OPERATION,
+  Aspect.RETRYABLE,
+  Aspect.EXECUTE_WITH_SELECTION
+]);
+
+module.exports = DistinctOperation;
diff --git a/node_modules/mongodb/lib/operations/drop.js b/node_modules/mongodb/lib/operations/drop.js
new file mode 100644
index 0000000..be03716
--- /dev/null
+++ b/node_modules/mongodb/lib/operations/drop.js
@@ -0,0 +1,53 @@
+'use strict';
+
+const Aspect = require('./operation').Aspect;
+const CommandOperation = require('./command');
+const defineAspects = require('./operation').defineAspects;
+const handleCallback = require('../utils').handleCallback;
+
+class DropOperation extends CommandOperation {
+  constructor(db, options) {
+    const finalOptions = Object.assign({}, options, db.s.options);
+
+    if (options.session) {
+      finalOptions.session = options.session;
+    }
+
+    super(db, finalOptions);
+  }
+
+  execute(callback) {
+    super.execute((err, result) => {
+      if (err) return handleCallback(callback, err);
+      if (result.ok) return handleCallback(callback, null, true);
+      handleCallback(callback, null, false);
+    });
+  }
+}
+
+defineAspects(DropOperation, Aspect.WRITE_OPERATION);
+
+class DropCollectionOperation extends DropOperation {
+  constructor(db, name, options) {
+    super(db, options);
+
+    this.name = name;
+    this.namespace = `${db.namespace}.${name}`;
+  }
+
+  _buildCommand() {
+    return { drop: this.name };
+  }
+}
+
+class DropDatabaseOperation extends DropOperation {
+  _buildCommand() {
+    return { dropDatabase: 1 };
+  }
+}
+
+module.exports = {
+  DropOperation,
+  DropCollectionOperation,
+  DropDatabaseOperation
+};
diff --git a/node_modules/mongodb/lib/operations/drop_index.js b/node_modules/mongodb/lib/operations/drop_index.js
new file mode 100644
index 0000000..a6ca783
--- /dev/null
+++ b/node_modules/mongodb/lib/operations/drop_index.js
@@ -0,0 +1,42 @@
+'use strict';
+
+const Aspect = require('./operation').Aspect;
+const defineAspects = require('./operation').defineAspects;
+const CommandOperation = require('./command');
+const applyWriteConcern = require('../utils').applyWriteConcern;
+const handleCallback = require('../utils').handleCallback;
+
+class DropIndexOperation extends CommandOperation {
+  constructor(collection, indexName, options) {
+    super(collection.s.db, options, collection);
+
+    this.collection = collection;
+    this.indexName = indexName;
+  }
+
+  _buildCommand() {
+    const collection = this.collection;
+    const indexName = this.indexName;
+    const options = this.options;
+
+    let cmd = { dropIndexes: collection.collectionName, index: indexName };
+
+    // Decorate command with writeConcern if supported
+    cmd = applyWriteConcern(cmd, { db: collection.s.db, collection }, options);
+
+    return cmd;
+  }
+
+  execute(callback) {
+    // Execute command
+    super.execute((err, result) => {
+      if (typeof callback !== 'function') return;
+      if (err) return handleCallback(callback, err, null);
+      handleCallback(callback, null, result);
+    });
+  }
+}
+
+defineAspects(DropIndexOperation, Aspect.WRITE_OPERATION);
+
+module.exports = DropIndexOperation;
diff --git a/node_modules/mongodb/lib/operations/drop_indexes.js b/node_modules/mongodb/lib/operations/drop_indexes.js
new file mode 100644
index 0000000..ed404ee
--- /dev/null
+++ b/node_modules/mongodb/lib/operations/drop_indexes.js
@@ -0,0 +1,23 @@
+'use strict';
+
+const Aspect = require('./operation').Aspect;
+const defineAspects = require('./operation').defineAspects;
+const DropIndexOperation = require('./drop_index');
+const handleCallback = require('../utils').handleCallback;
+
+class DropIndexesOperation extends DropIndexOperation {
+  constructor(collection, options) {
+    super(collection, '*', options);
+  }
+
+  execute(callback) {
+    super.execute(err => {
+      if (err) return handleCallback(callback, err, false);
+      handleCallback(callback, null, true);
+    });
+  }
+}
+
+defineAspects(DropIndexesOperation, Aspect.WRITE_OPERATION);
+
+module.exports = DropIndexesOperation;
diff --git a/node_modules/mongodb/lib/operations/estimated_document_count.js b/node_modules/mongodb/lib/operations/estimated_document_count.js
new file mode 100644
index 0000000..e2d6556
--- /dev/null
+++ b/node_modules/mongodb/lib/operations/estimated_document_count.js
@@ -0,0 +1,58 @@
+'use strict';
+
+const Aspect = require('./operation').Aspect;
+const defineAspects = require('./operation').defineAspects;
+const CommandOperationV2 = require('./command_v2');
+
+class EstimatedDocumentCountOperation extends CommandOperationV2 {
+  constructor(collection, query, options) {
+    if (typeof options === 'undefined') {
+      options = query;
+      query = undefined;
+    }
+
+    super(collection, options);
+    this.collectionName = collection.s.namespace.collection;
+    if (query) {
+      this.query = query;
+    }
+  }
+
+  execute(server, callback) {
+    const options = this.options;
+    const cmd = { count: this.collectionName };
+
+    if (this.query) {
+      cmd.query = this.query;
+    }
+
+    if (typeof options.skip === 'number') {
+      cmd.skip = options.skip;
+    }
+
+    if (typeof options.limit === 'number') {
+      cmd.limit = options.limit;
+    }
+
+    if (options.hint) {
+      cmd.hint = options.hint;
+    }
+
+    super.executeCommand(server, cmd, (err, response) => {
+      if (err) {
+        callback(err);
+        return;
+      }
+
+      callback(null, response.n);
+    });
+  }
+}
+
+defineAspects(EstimatedDocumentCountOperation, [
+  Aspect.READ_OPERATION,
+  Aspect.RETRYABLE,
+  Aspect.EXECUTE_WITH_SELECTION
+]);
+
+module.exports = EstimatedDocumentCountOperation;
diff --git a/node_modules/mongodb/lib/operations/execute_db_admin_command.js b/node_modules/mongodb/lib/operations/execute_db_admin_command.js
new file mode 100644
index 0000000..d15fc8e
--- /dev/null
+++ b/node_modules/mongodb/lib/operations/execute_db_admin_command.js
@@ -0,0 +1,34 @@
+'use strict';
+
+const OperationBase = require('./operation').OperationBase;
+const handleCallback = require('../utils').handleCallback;
+const MongoError = require('../core').MongoError;
+const MongoDBNamespace = require('../utils').MongoDBNamespace;
+
+class ExecuteDbAdminCommandOperation extends OperationBase {
+  constructor(db, selector, options) {
+    super(options);
+
+    this.db = db;
+    this.selector = selector;
+  }
+
+  execute(callback) {
+    const db = this.db;
+    const selector = this.selector;
+    const options = this.options;
+
+    const namespace = new MongoDBNamespace('admin', '$cmd');
+    db.s.topology.command(namespace, selector, options, (err, result) => {
+      // Did the user destroy the topology
+      if (db.serverConfig && db.serverConfig.isDestroyed()) {
+        return callback(new MongoError('topology was destroyed'));
+      }
+
+      if (err) return handleCallback(callback, err);
+      handleCallback(callback, null, result.result);
+    });
+  }
+}
+
+module.exports = ExecuteDbAdminCommandOperation;
diff --git a/node_modules/mongodb/lib/operations/execute_operation.js b/node_modules/mongodb/lib/operations/execute_operation.js
new file mode 100644
index 0000000..80d5785
--- /dev/null
+++ b/node_modules/mongodb/lib/operations/execute_operation.js
@@ -0,0 +1,186 @@
+'use strict';
+
+const MongoError = require('../core/error').MongoError;
+const Aspect = require('./operation').Aspect;
+const OperationBase = require('./operation').OperationBase;
+const ReadPreference = require('../core/topologies/read_preference');
+const isRetryableError = require('../core/error').isRetryableError;
+const maxWireVersion = require('../core/utils').maxWireVersion;
+const isUnifiedTopology = require('../core/utils').isUnifiedTopology;
+
+/**
+ * Executes the given operation with provided arguments.
+ *
+ * This method reduces large amounts of duplication in the entire codebase by providing
+ * a single point for determining whether callbacks or promises should be used. Additionally
+ * it allows for a single point of entry to provide features such as implicit sessions, which
+ * are required by the Driver Sessions specification in the event that a ClientSession is
+ * not provided
+ *
+ * @param {object} topology The topology to execute this operation on
+ * @param {Operation} operation The operation to execute
+ * @param {function} callback The command result callback
+ */
+function executeOperation(topology, operation, callback) {
+  if (topology == null) {
+    throw new TypeError('This method requires a valid topology instance');
+  }
+
+  if (!(operation instanceof OperationBase)) {
+    throw new TypeError('This method requires a valid operation instance');
+  }
+
+  if (isUnifiedTopology(topology) && topology.shouldCheckForSessionSupport()) {
+    return selectServerForSessionSupport(topology, operation, callback);
+  }
+
+  const Promise = topology.s.promiseLibrary;
+
+  // The driver sessions spec mandates that we implicitly create sessions for operations
+  // that are not explicitly provided with a session.
+  let session, owner;
+  if (topology.hasSessionSupport()) {
+    if (operation.session == null) {
+      owner = Symbol();
+      session = topology.startSession({ owner });
+      operation.session = session;
+    } else if (operation.session.hasEnded) {
+      throw new MongoError('Use of expired sessions is not permitted');
+    }
+  }
+
+  let result;
+  if (typeof callback !== 'function') {
+    result = new Promise((resolve, reject) => {
+      callback = (err, res) => {
+        if (err) return reject(err);
+        resolve(res);
+      };
+    });
+  }
+
+  function executeCallback(err, result) {
+    if (session && session.owner === owner) {
+      session.endSession();
+      if (operation.session === session) {
+        operation.clearSession();
+      }
+    }
+
+    callback(err, result);
+  }
+
+  try {
+    if (operation.hasAspect(Aspect.EXECUTE_WITH_SELECTION)) {
+      executeWithServerSelection(topology, operation, executeCallback);
+    } else {
+      operation.execute(executeCallback);
+    }
+  } catch (e) {
+    if (session && session.owner === owner) {
+      session.endSession();
+      if (operation.session === session) {
+        operation.clearSession();
+      }
+    }
+
+    throw e;
+  }
+
+  return result;
+}
+
+function supportsRetryableReads(server) {
+  return maxWireVersion(server) >= 6;
+}
+
+function executeWithServerSelection(topology, operation, callback) {
+  const readPreference = operation.readPreference || ReadPreference.primary;
+  const inTransaction = operation.session && operation.session.inTransaction();
+
+  if (inTransaction && !readPreference.equals(ReadPreference.primary)) {
+    callback(
+      new MongoError(
+        `Read preference in a transaction must be primary, not: ${readPreference.mode}`
+      )
+    );
+
+    return;
+  }
+
+  const serverSelectionOptions = {
+    readPreference,
+    session: operation.session
+  };
+
+  function callbackWithRetry(err, result) {
+    if (err == null) {
+      return callback(null, result);
+    }
+
+    if (!isRetryableError(err)) {
+      return callback(err);
+    }
+
+    // select a new server, and attempt to retry the operation
+    topology.selectServer(serverSelectionOptions, (err, server) => {
+      if (err || !supportsRetryableReads(server)) {
+        callback(err, null);
+        return;
+      }
+
+      operation.execute(server, callback);
+    });
+  }
+
+  // select a server, and execute the operation against it
+  topology.selectServer(serverSelectionOptions, (err, server) => {
+    if (err) {
+      callback(err, null);
+      return;
+    }
+
+    const shouldRetryReads =
+      topology.s.options.retryReads !== false &&
+      operation.session &&
+      !inTransaction &&
+      supportsRetryableReads(server) &&
+      operation.canRetryRead;
+
+    if (operation.hasAspect(Aspect.RETRYABLE) && shouldRetryReads) {
+      operation.execute(server, callbackWithRetry);
+      return;
+    }
+
+    operation.execute(server, callback);
+  });
+}
+
+// TODO: This is only supported for unified topology, it should go away once
+//       we remove support for legacy topology types.
+function selectServerForSessionSupport(topology, operation, callback) {
+  const Promise = topology.s.promiseLibrary;
+
+  let result;
+  if (typeof callback !== 'function') {
+    result = new Promise((resolve, reject) => {
+      callback = (err, result) => {
+        if (err) return reject(err);
+        resolve(result);
+      };
+    });
+  }
+
+  topology.selectServer(ReadPreference.primaryPreferred, err => {
+    if (err) {
+      callback(err);
+      return;
+    }
+
+    executeOperation(topology, operation, callback);
+  });
+
+  return result;
+}
+
+module.exports = executeOperation;
diff --git a/node_modules/mongodb/lib/operations/find.js b/node_modules/mongodb/lib/operations/find.js
new file mode 100644
index 0000000..09cb9a9
--- /dev/null
+++ b/node_modules/mongodb/lib/operations/find.js
@@ -0,0 +1,40 @@
+'use strict';
+
+const OperationBase = require('./operation').OperationBase;
+const Aspect = require('./operation').Aspect;
+const defineAspects = require('./operation').defineAspects;
+const ReadPreference = require('../core').ReadPreference;
+const maxWireVersion = require('../core/utils').maxWireVersion;
+const MongoError = require('../core/error').MongoError;
+
+class FindOperation extends OperationBase {
+  constructor(collection, ns, command, options) {
+    super(options);
+
+    this.ns = ns;
+    this.cmd = command;
+    this.readPreference = ReadPreference.resolve(collection, this.options);
+  }
+
+  execute(server, callback) {
+    // copied from `CommandOperationV2`, to be subclassed in the future
+    this.server = server;
+
+    if (typeof this.cmd.allowDiskUse !== 'undefined' && maxWireVersion(server) < 4) {
+      callback(new MongoError('The `allowDiskUse` option is not supported on MongoDB < 3.2'));
+      return;
+    }
+
+    // TOOD: use `MongoDBNamespace` through and through
+    const cursorState = this.cursorState || {};
+    server.query(this.ns.toString(), this.cmd, cursorState, this.options, callback);
+  }
+}
+
+defineAspects(FindOperation, [
+  Aspect.READ_OPERATION,
+  Aspect.RETRYABLE,
+  Aspect.EXECUTE_WITH_SELECTION
+]);
+
+module.exports = FindOperation;
diff --git a/node_modules/mongodb/lib/operations/find_and_modify.js b/node_modules/mongodb/lib/operations/find_and_modify.js
new file mode 100644
index 0000000..03711ee
--- /dev/null
+++ b/node_modules/mongodb/lib/operations/find_and_modify.js
@@ -0,0 +1,115 @@
+'use strict';
+
+const OperationBase = require('./operation').OperationBase;
+const applyRetryableWrites = require('../utils').applyRetryableWrites;
+const applyWriteConcern = require('../utils').applyWriteConcern;
+const decorateWithCollation = require('../utils').decorateWithCollation;
+const executeCommand = require('./db_ops').executeCommand;
+const formattedOrderClause = require('../utils').formattedOrderClause;
+const handleCallback = require('../utils').handleCallback;
+const ReadPreference = require('../core').ReadPreference;
+const maxWireVersion = require('../core/utils').maxWireVersion;
+const MongoError = require('../error').MongoError;
+
+class FindAndModifyOperation extends OperationBase {
+  constructor(collection, query, sort, doc, options) {
+    super(options);
+
+    this.collection = collection;
+    this.query = query;
+    this.sort = sort;
+    this.doc = doc;
+  }
+
+  execute(callback) {
+    const coll = this.collection;
+    const query = this.query;
+    const sort = formattedOrderClause(this.sort);
+    const doc = this.doc;
+    let options = this.options;
+
+    // Create findAndModify command object
+    const queryObject = {
+      findAndModify: coll.collectionName,
+      query: query
+    };
+
+    if (sort) {
+      queryObject.sort = sort;
+    }
+
+    queryObject.new = options.new ? true : false;
+    queryObject.remove = options.remove ? true : false;
+    queryObject.upsert = options.upsert ? true : false;
+
+    const projection = options.projection || options.fields;
+
+    if (projection) {
+      queryObject.fields = projection;
+    }
+
+    if (options.arrayFilters) {
+      queryObject.arrayFilters = options.arrayFilters;
+    }
+
+    if (doc && !options.remove) {
+      queryObject.update = doc;
+    }
+
+    if (options.maxTimeMS) queryObject.maxTimeMS = options.maxTimeMS;
+
+    // Either use override on the function, or go back to default on either the collection
+    // level or db
+    options.serializeFunctions = options.serializeFunctions || coll.s.serializeFunctions;
+
+    // No check on the documents
+    options.checkKeys = false;
+
+    // Final options for retryable writes and write concern
+    options = applyRetryableWrites(options, coll.s.db);
+    options = applyWriteConcern(options, { db: coll.s.db, collection: coll }, options);
+
+    // Decorate the findAndModify command with the write Concern
+    if (options.writeConcern) {
+      queryObject.writeConcern = options.writeConcern;
+    }
+
+    // Have we specified bypassDocumentValidation
+    if (options.bypassDocumentValidation === true) {
+      queryObject.bypassDocumentValidation = options.bypassDocumentValidation;
+    }
+
+    options.readPreference = ReadPreference.primary;
+
+    // Have we specified collation
+    try {
+      decorateWithCollation(queryObject, coll, options);
+    } catch (err) {
+      return callback(err, null);
+    }
+
+    if (options.hint) {
+      // TODO: once this method becomes a CommandOperationV2 we will have the server
+      // in place to check.
+      const unacknowledgedWrite = options.writeConcern && options.writeConcern.w === 0;
+      if (unacknowledgedWrite || maxWireVersion(coll.s.topology) < 8) {
+        callback(
+          new MongoError('The current topology does not support a hint on findAndModify commands')
+        );
+
+        return;
+      }
+
+      queryObject.hint = options.hint;
+    }
+
+    // Execute the command
+    executeCommand(coll.s.db, queryObject, options, (err, result) => {
+      if (err) return handleCallback(callback, err, null);
+
+      return handleCallback(callback, null, result);
+    });
+  }
+}
+
+module.exports = FindAndModifyOperation;
diff --git a/node_modules/mongodb/lib/operations/find_one.js b/node_modules/mongodb/lib/operations/find_one.js
new file mode 100644
index 0000000..b584db6
--- /dev/null
+++ b/node_modules/mongodb/lib/operations/find_one.js
@@ -0,0 +1,37 @@
+'use strict';
+
+const handleCallback = require('../utils').handleCallback;
+const OperationBase = require('./operation').OperationBase;
+const toError = require('../utils').toError;
+
+class FindOneOperation extends OperationBase {
+  constructor(collection, query, options) {
+    super(options);
+
+    this.collection = collection;
+    this.query = query;
+  }
+
+  execute(callback) {
+    const coll = this.collection;
+    const query = this.query;
+    const options = this.options;
+
+    try {
+      const cursor = coll
+        .find(query, options)
+        .limit(-1)
+        .batchSize(1);
+
+      // Return the item
+      cursor.next((err, item) => {
+        if (err != null) return handleCallback(callback, toError(err), null);
+        handleCallback(callback, null, item);
+      });
+    } catch (e) {
+      callback(e);
+    }
+  }
+}
+
+module.exports = FindOneOperation;
diff --git a/node_modules/mongodb/lib/operations/find_one_and_delete.js b/node_modules/mongodb/lib/operations/find_one_and_delete.js
new file mode 100644
index 0000000..eaf3287
--- /dev/null
+++ b/node_modules/mongodb/lib/operations/find_one_and_delete.js
@@ -0,0 +1,21 @@
+'use strict';
+
+const FindAndModifyOperation = require('./find_and_modify');
+
+class FindOneAndDeleteOperation extends FindAndModifyOperation {
+  constructor(collection, filter, options) {
+    // Final options
+    const finalOptions = Object.assign({}, options);
+    finalOptions.fields = options.projection;
+    finalOptions.remove = true;
+
+    // Basic validation
+    if (filter == null || typeof filter !== 'object') {
+      throw new TypeError('Filter parameter must be an object');
+    }
+
+    super(collection, filter, finalOptions.sort, null, finalOptions);
+  }
+}
+
+module.exports = FindOneAndDeleteOperation;
diff --git a/node_modules/mongodb/lib/operations/find_one_and_replace.js b/node_modules/mongodb/lib/operations/find_one_and_replace.js
new file mode 100644
index 0000000..f068cdf
--- /dev/null
+++ b/node_modules/mongodb/lib/operations/find_one_and_replace.js
@@ -0,0 +1,31 @@
+'use strict';
+
+const FindAndModifyOperation = require('./find_and_modify');
+const hasAtomicOperators = require('../utils').hasAtomicOperators;
+
+class FindOneAndReplaceOperation extends FindAndModifyOperation {
+  constructor(collection, filter, replacement, options) {
+    // Final options
+    const finalOptions = Object.assign({}, options);
+    finalOptions.fields = options.projection;
+    finalOptions.update = true;
+    finalOptions.new = options.returnOriginal !== void 0 ? !options.returnOriginal : false;
+    finalOptions.upsert = options.upsert !== void 0 ? !!options.upsert : false;
+
+    if (filter == null || typeof filter !== 'object') {
+      throw new TypeError('Filter parameter must be an object');
+    }
+
+    if (replacement == null || typeof replacement !== 'object') {
+      throw new TypeError('Replacement parameter must be an object');
+    }
+
+    if (hasAtomicOperators(replacement)) {
+      throw new TypeError('Replacement document must not contain atomic operators');
+    }
+
+    super(collection, filter, finalOptions.sort, replacement, finalOptions);
+  }
+}
+
+module.exports = FindOneAndReplaceOperation;
diff --git a/node_modules/mongodb/lib/operations/find_one_and_update.js b/node_modules/mongodb/lib/operations/find_one_and_update.js
new file mode 100644
index 0000000..5ec8be5
--- /dev/null
+++ b/node_modules/mongodb/lib/operations/find_one_and_update.js
@@ -0,0 +1,32 @@
+'use strict';
+
+const FindAndModifyOperation = require('./find_and_modify');
+const hasAtomicOperators = require('../utils').hasAtomicOperators;
+
+class FindOneAndUpdateOperation extends FindAndModifyOperation {
+  constructor(collection, filter, update, options) {
+    // Final options
+    const finalOptions = Object.assign({}, options);
+    finalOptions.fields = options.projection;
+    finalOptions.update = true;
+    finalOptions.new =
+      typeof options.returnOriginal === 'boolean' ? !options.returnOriginal : false;
+    finalOptions.upsert = typeof options.upsert === 'boolean' ? options.upsert : false;
+
+    if (filter == null || typeof filter !== 'object') {
+      throw new TypeError('Filter parameter must be an object');
+    }
+
+    if (update == null || typeof update !== 'object') {
+      throw new TypeError('Update parameter must be an object');
+    }
+
+    if (!hasAtomicOperators(update)) {
+      throw new TypeError('Update document requires atomic operators');
+    }
+
+    super(collection, filter, finalOptions.sort, update, finalOptions);
+  }
+}
+
+module.exports = FindOneAndUpdateOperation;
diff --git a/node_modules/mongodb/lib/operations/geo_haystack_search.js b/node_modules/mongodb/lib/operations/geo_haystack_search.js
new file mode 100644
index 0000000..7c8654d
--- /dev/null
+++ b/node_modules/mongodb/lib/operations/geo_haystack_search.js
@@ -0,0 +1,79 @@
+'use strict';
+
+const Aspect = require('./operation').Aspect;
+const defineAspects = require('./operation').defineAspects;
+const OperationBase = require('./operation').OperationBase;
+const decorateCommand = require('../utils').decorateCommand;
+const decorateWithReadConcern = require('../utils').decorateWithReadConcern;
+const executeCommand = require('./db_ops').executeCommand;
+const handleCallback = require('../utils').handleCallback;
+const ReadPreference = require('../core').ReadPreference;
+const toError = require('../utils').toError;
+
+/**
+ * Execute a geo search using a geo haystack index on a collection.
+ *
+ * @class
+ * @property {Collection} a Collection instance.
+ * @property {number} x Point to search on the x axis, ensure the indexes are ordered in the same order.
+ * @property {number} y Point to search on the y axis, ensure the indexes are ordered in the same order.
+ * @property {object} [options] Optional settings. See Collection.prototype.geoHaystackSearch for a list of options.
+ */
+class GeoHaystackSearchOperation extends OperationBase {
+  /**
+   * Construct a GeoHaystackSearch operation.
+   *
+   * @param {Collection} a Collection instance.
+   * @param {number} x Point to search on the x axis, ensure the indexes are ordered in the same order.
+   * @param {number} y Point to search on the y axis, ensure the indexes are ordered in the same order.
+   * @param {object} [options] Optional settings. See Collection.prototype.geoHaystackSearch for a list of options.
+   */
+  constructor(collection, x, y, options) {
+    super(options);
+
+    this.collection = collection;
+    this.x = x;
+    this.y = y;
+  }
+
+  /**
+   * Execute the operation.
+   *
+   * @param {Collection~resultCallback} [callback] The command result callback
+   */
+  execute(callback) {
+    const coll = this.collection;
+    const x = this.x;
+    const y = this.y;
+    let options = this.options;
+
+    // Build command object
+    let commandObject = {
+      geoSearch: coll.collectionName,
+      near: [x, y]
+    };
+
+    // Remove read preference from hash if it exists
+    commandObject = decorateCommand(commandObject, options, ['readPreference', 'session']);
+
+    options = Object.assign({}, options);
+    // Ensure we have the right read preference inheritance
+    options.readPreference = ReadPreference.resolve(coll, options);
+
+    // Do we have a readConcern specified
+    decorateWithReadConcern(commandObject, coll, options);
+
+    // Execute the command
+    executeCommand(coll.s.db, commandObject, options, (err, res) => {
+      if (err) return handleCallback(callback, err);
+      if (res.err || res.errmsg) handleCallback(callback, toError(res));
+      // should we only be returning res.results here? Not sure if the user
+      // should see the other return information
+      handleCallback(callback, null, res);
+    });
+  }
+}
+
+defineAspects(GeoHaystackSearchOperation, Aspect.READ_OPERATION);
+
+module.exports = GeoHaystackSearchOperation;
diff --git a/node_modules/mongodb/lib/operations/index_exists.js b/node_modules/mongodb/lib/operations/index_exists.js
new file mode 100644
index 0000000..bd9dc0e
--- /dev/null
+++ b/node_modules/mongodb/lib/operations/index_exists.js
@@ -0,0 +1,39 @@
+'use strict';
+
+const OperationBase = require('./operation').OperationBase;
+const handleCallback = require('../utils').handleCallback;
+const indexInformationDb = require('./db_ops').indexInformation;
+
+class IndexExistsOperation extends OperationBase {
+  constructor(collection, indexes, options) {
+    super(options);
+
+    this.collection = collection;
+    this.indexes = indexes;
+  }
+
+  execute(callback) {
+    const coll = this.collection;
+    const indexes = this.indexes;
+    const options = this.options;
+
+    indexInformationDb(coll.s.db, coll.collectionName, options, (err, indexInformation) => {
+      // If we have an error return
+      if (err != null) return handleCallback(callback, err, null);
+      // Let's check for the index names
+      if (!Array.isArray(indexes))
+        return handleCallback(callback, null, indexInformation[indexes] != null);
+      // Check in list of indexes
+      for (let i = 0; i < indexes.length; i++) {
+        if (indexInformation[indexes[i]] == null) {
+          return handleCallback(callback, null, false);
+        }
+      }
+
+      // All keys found return true
+      return handleCallback(callback, null, true);
+    });
+  }
+}
+
+module.exports = IndexExistsOperation;
diff --git a/node_modules/mongodb/lib/operations/index_information.js b/node_modules/mongodb/lib/operations/index_information.js
new file mode 100644
index 0000000..b18a603
--- /dev/null
+++ b/node_modules/mongodb/lib/operations/index_information.js
@@ -0,0 +1,23 @@
+'use strict';
+
+const OperationBase = require('./operation').OperationBase;
+const indexInformation = require('./common_functions').indexInformation;
+
+class IndexInformationOperation extends OperationBase {
+  constructor(db, name, options) {
+    super(options);
+
+    this.db = db;
+    this.name = name;
+  }
+
+  execute(callback) {
+    const db = this.db;
+    const name = this.name;
+    const options = this.options;
+
+    indexInformation(db, name, options, callback);
+  }
+}
+
+module.exports = IndexInformationOperation;
diff --git a/node_modules/mongodb/lib/operations/indexes.js b/node_modules/mongodb/lib/operations/indexes.js
new file mode 100644
index 0000000..e29a88a
--- /dev/null
+++ b/node_modules/mongodb/lib/operations/indexes.js
@@ -0,0 +1,22 @@
+'use strict';
+
+const OperationBase = require('./operation').OperationBase;
+const indexInformation = require('./common_functions').indexInformation;
+
+class IndexesOperation extends OperationBase {
+  constructor(collection, options) {
+    super(options);
+
+    this.collection = collection;
+  }
+
+  execute(callback) {
+    const coll = this.collection;
+    let options = this.options;
+
+    options = Object.assign({}, { full: true }, options);
+    indexInformation(coll.s.db, coll.collectionName, options, callback);
+  }
+}
+
+module.exports = IndexesOperation;
diff --git a/node_modules/mongodb/lib/operations/insert_many.js b/node_modules/mongodb/lib/operations/insert_many.js
new file mode 100644
index 0000000..460a535
--- /dev/null
+++ b/node_modules/mongodb/lib/operations/insert_many.js
@@ -0,0 +1,63 @@
+'use strict';
+
+const OperationBase = require('./operation').OperationBase;
+const BulkWriteOperation = require('./bulk_write');
+const MongoError = require('../core').MongoError;
+const prepareDocs = require('./common_functions').prepareDocs;
+
+class InsertManyOperation extends OperationBase {
+  constructor(collection, docs, options) {
+    super(options);
+
+    this.collection = collection;
+    this.docs = docs;
+  }
+
+  execute(callback) {
+    const coll = this.collection;
+    let docs = this.docs;
+    const options = this.options;
+
+    if (!Array.isArray(docs)) {
+      return callback(
+        MongoError.create({ message: 'docs parameter must be an array of documents', driver: true })
+      );
+    }
+
+    // If keep going set unordered
+    options['serializeFunctions'] = options['serializeFunctions'] || coll.s.serializeFunctions;
+
+    docs = prepareDocs(coll, docs, options);
+
+    // Generate the bulk write operations
+    const operations = [
+      {
+        insertMany: docs
+      }
+    ];
+
+    const bulkWriteOperation = new BulkWriteOperation(coll, operations, options);
+
+    bulkWriteOperation.execute((err, result) => {
+      if (err) return callback(err, null);
+      callback(null, mapInsertManyResults(docs, result));
+    });
+  }
+}
+
+function mapInsertManyResults(docs, r) {
+  const finalResult = {
+    result: { ok: 1, n: r.insertedCount },
+    ops: docs,
+    insertedCount: r.insertedCount,
+    insertedIds: r.insertedIds
+  };
+
+  if (r.getLastOp()) {
+    finalResult.result.opTime = r.getLastOp();
+  }
+
+  return finalResult;
+}
+
+module.exports = InsertManyOperation;
diff --git a/node_modules/mongodb/lib/operations/insert_one.js b/node_modules/mongodb/lib/operations/insert_one.js
new file mode 100644
index 0000000..5e70880
--- /dev/null
+++ b/node_modules/mongodb/lib/operations/insert_one.js
@@ -0,0 +1,39 @@
+'use strict';
+
+const MongoError = require('../core').MongoError;
+const OperationBase = require('./operation').OperationBase;
+const insertDocuments = require('./common_functions').insertDocuments;
+
+class InsertOneOperation extends OperationBase {
+  constructor(collection, doc, options) {
+    super(options);
+
+    this.collection = collection;
+    this.doc = doc;
+  }
+
+  execute(callback) {
+    const coll = this.collection;
+    const doc = this.doc;
+    const options = this.options;
+
+    if (Array.isArray(doc)) {
+      return callback(
+        MongoError.create({ message: 'doc parameter must be an object', driver: true })
+      );
+    }
+
+    insertDocuments(coll, [doc], options, (err, r) => {
+      if (callback == null) return;
+      if (err && callback) return callback(err);
+      // Workaround for pre 2.6 servers
+      if (r == null) return callback(null, { result: { ok: 1 } });
+      // Add values to top level to ensure crud spec compatibility
+      r.insertedCount = r.result.n;
+      r.insertedId = doc._id;
+      if (callback) callback(null, r);
+    });
+  }
+}
+
+module.exports = InsertOneOperation;
diff --git a/node_modules/mongodb/lib/operations/is_capped.js b/node_modules/mongodb/lib/operations/is_capped.js
new file mode 100644
index 0000000..3bfd9ff
--- /dev/null
+++ b/node_modules/mongodb/lib/operations/is_capped.js
@@ -0,0 +1,19 @@
+'use strict';
+
+const OptionsOperation = require('./options_operation');
+const handleCallback = require('../utils').handleCallback;
+
+class IsCappedOperation extends OptionsOperation {
+  constructor(collection, options) {
+    super(collection, options);
+  }
+
+  execute(callback) {
+    super.execute((err, document) => {
+      if (err) return handleCallback(callback, err);
+      handleCallback(callback, null, !!(document && document.capped));
+    });
+  }
+}
+
+module.exports = IsCappedOperation;
diff --git a/node_modules/mongodb/lib/operations/list_collections.js b/node_modules/mongodb/lib/operations/list_collections.js
new file mode 100644
index 0000000..ee01d31
--- /dev/null
+++ b/node_modules/mongodb/lib/operations/list_collections.js
@@ -0,0 +1,106 @@
+'use strict';
+
+const CommandOperationV2 = require('./command_v2');
+const Aspect = require('./operation').Aspect;
+const defineAspects = require('./operation').defineAspects;
+const maxWireVersion = require('../core/utils').maxWireVersion;
+const CONSTANTS = require('../constants');
+
+const LIST_COLLECTIONS_WIRE_VERSION = 3;
+
+function listCollectionsTransforms(databaseName) {
+  const matching = `${databaseName}.`;
+
+  return {
+    doc: doc => {
+      const index = doc.name.indexOf(matching);
+      // Remove database name if available
+      if (doc.name && index === 0) {
+        doc.name = doc.name.substr(index + matching.length);
+      }
+
+      return doc;
+    }
+  };
+}
+
+class ListCollectionsOperation extends CommandOperationV2 {
+  constructor(db, filter, options) {
+    super(db, options, { fullResponse: true });
+
+    this.db = db;
+    this.filter = filter;
+    this.nameOnly = !!this.options.nameOnly;
+
+    if (typeof this.options.batchSize === 'number') {
+      this.batchSize = this.options.batchSize;
+    }
+  }
+
+  execute(server, callback) {
+    if (maxWireVersion(server) < LIST_COLLECTIONS_WIRE_VERSION) {
+      let filter = this.filter;
+      const databaseName = this.db.s.namespace.db;
+
+      // If we have legacy mode and have not provided a full db name filter it
+      if (
+        typeof filter.name === 'string' &&
+        !new RegExp('^' + databaseName + '\\.').test(filter.name)
+      ) {
+        filter = Object.assign({}, filter);
+        filter.name = this.db.s.namespace.withCollection(filter.name).toString();
+      }
+
+      // No filter, filter by current database
+      if (filter == null) {
+        filter.name = `/${databaseName}/`;
+      }
+
+      // Rewrite the filter to use $and to filter out indexes
+      if (filter.name) {
+        filter = { $and: [{ name: filter.name }, { name: /^((?!\$).)*$/ }] };
+      } else {
+        filter = { name: /^((?!\$).)*$/ };
+      }
+
+      const transforms = listCollectionsTransforms(databaseName);
+      server.query(
+        `${databaseName}.${CONSTANTS.SYSTEM_NAMESPACE_COLLECTION}`,
+        { query: filter },
+        { batchSize: this.batchSize || 1000 },
+        {},
+        (err, result) => {
+          if (
+            result &&
+            result.message &&
+            result.message.documents &&
+            Array.isArray(result.message.documents)
+          ) {
+            result.message.documents = result.message.documents.map(transforms.doc);
+          }
+
+          callback(err, result);
+        }
+      );
+
+      return;
+    }
+
+    const command = {
+      listCollections: 1,
+      filter: this.filter,
+      cursor: this.batchSize ? { batchSize: this.batchSize } : {},
+      nameOnly: this.nameOnly
+    };
+
+    return super.executeCommand(server, command, callback);
+  }
+}
+
+defineAspects(ListCollectionsOperation, [
+  Aspect.READ_OPERATION,
+  Aspect.RETRYABLE,
+  Aspect.EXECUTE_WITH_SELECTION
+]);
+
+module.exports = ListCollectionsOperation;
diff --git a/node_modules/mongodb/lib/operations/list_databases.js b/node_modules/mongodb/lib/operations/list_databases.js
new file mode 100644
index 0000000..62b2606
--- /dev/null
+++ b/node_modules/mongodb/lib/operations/list_databases.js
@@ -0,0 +1,38 @@
+'use strict';
+
+const CommandOperationV2 = require('./command_v2');
+const Aspect = require('./operation').Aspect;
+const defineAspects = require('./operation').defineAspects;
+const MongoDBNamespace = require('../utils').MongoDBNamespace;
+
+class ListDatabasesOperation extends CommandOperationV2 {
+  constructor(db, options) {
+    super(db, options);
+    this.ns = new MongoDBNamespace('admin', '$cmd');
+  }
+
+  execute(server, callback) {
+    const cmd = { listDatabases: 1 };
+    if (this.options.nameOnly) {
+      cmd.nameOnly = Number(cmd.nameOnly);
+    }
+
+    if (this.options.filter) {
+      cmd.filter = this.options.filter;
+    }
+
+    if (typeof this.options.authorizedDatabases === 'boolean') {
+      cmd.authorizedDatabases = this.options.authorizedDatabases;
+    }
+
+    super.executeCommand(server, cmd, callback);
+  }
+}
+
+defineAspects(ListDatabasesOperation, [
+  Aspect.READ_OPERATION,
+  Aspect.RETRYABLE,
+  Aspect.EXECUTE_WITH_SELECTION
+]);
+
+module.exports = ListDatabasesOperation;
diff --git a/node_modules/mongodb/lib/operations/list_indexes.js b/node_modules/mongodb/lib/operations/list_indexes.js
new file mode 100644
index 0000000..302a31b
--- /dev/null
+++ b/node_modules/mongodb/lib/operations/list_indexes.js
@@ -0,0 +1,42 @@
+'use strict';
+
+const CommandOperationV2 = require('./command_v2');
+const Aspect = require('./operation').Aspect;
+const defineAspects = require('./operation').defineAspects;
+const maxWireVersion = require('../core/utils').maxWireVersion;
+
+const LIST_INDEXES_WIRE_VERSION = 3;
+
+class ListIndexesOperation extends CommandOperationV2 {
+  constructor(collection, options) {
+    super(collection, options, { fullResponse: true });
+
+    this.collectionNamespace = collection.s.namespace;
+  }
+
+  execute(server, callback) {
+    const serverWireVersion = maxWireVersion(server);
+    if (serverWireVersion < LIST_INDEXES_WIRE_VERSION) {
+      const systemIndexesNS = this.collectionNamespace.withCollection('system.indexes').toString();
+      const collectionNS = this.collectionNamespace.toString();
+
+      server.query(systemIndexesNS, { query: { ns: collectionNS } }, {}, this.options, callback);
+      return;
+    }
+
+    const cursor = this.options.batchSize ? { batchSize: this.options.batchSize } : {};
+    super.executeCommand(
+      server,
+      { listIndexes: this.collectionNamespace.collection, cursor },
+      callback
+    );
+  }
+}
+
+defineAspects(ListIndexesOperation, [
+  Aspect.READ_OPERATION,
+  Aspect.RETRYABLE,
+  Aspect.EXECUTE_WITH_SELECTION
+]);
+
+module.exports = ListIndexesOperation;
diff --git a/node_modules/mongodb/lib/operations/map_reduce.js b/node_modules/mongodb/lib/operations/map_reduce.js
new file mode 100644
index 0000000..febba58
--- /dev/null
+++ b/node_modules/mongodb/lib/operations/map_reduce.js
@@ -0,0 +1,190 @@
+'use strict';
+
+const applyWriteConcern = require('../utils').applyWriteConcern;
+const Code = require('../core').BSON.Code;
+const decorateWithCollation = require('../utils').decorateWithCollation;
+const decorateWithReadConcern = require('../utils').decorateWithReadConcern;
+const executeCommand = require('./db_ops').executeCommand;
+const handleCallback = require('../utils').handleCallback;
+const isObject = require('../utils').isObject;
+const loadDb = require('../dynamic_loaders').loadDb;
+const OperationBase = require('./operation').OperationBase;
+const ReadPreference = require('../core').ReadPreference;
+const toError = require('../utils').toError;
+
+const exclusionList = [
+  'readPreference',
+  'session',
+  'bypassDocumentValidation',
+  'w',
+  'wtimeout',
+  'j',
+  'writeConcern'
+];
+
+/**
+ * Run Map Reduce across a collection. Be aware that the inline option for out will return an array of results not a collection.
+ *
+ * @class
+ * @property {Collection} a Collection instance.
+ * @property {(function|string)} map The mapping function.
+ * @property {(function|string)} reduce The reduce function.
+ * @property {object} [options] Optional settings. See Collection.prototype.mapReduce for a list of options.
+ */
+class MapReduceOperation extends OperationBase {
+  /**
+   * Constructs a MapReduce operation.
+   *
+   * @param {Collection} a Collection instance.
+   * @param {(function|string)} map The mapping function.
+   * @param {(function|string)} reduce The reduce function.
+   * @param {object} [options] Optional settings. See Collection.prototype.mapReduce for a list of options.
+   */
+  constructor(collection, map, reduce, options) {
+    super(options);
+
+    this.collection = collection;
+    this.map = map;
+    this.reduce = reduce;
+  }
+
+  /**
+   * Execute the operation.
+   *
+   * @param {Collection~resultCallback} [callback] The command result callback
+   */
+  execute(callback) {
+    const coll = this.collection;
+    const map = this.map;
+    const reduce = this.reduce;
+    let options = this.options;
+
+    const mapCommandHash = {
+      mapReduce: coll.collectionName,
+      map: map,
+      reduce: reduce
+    };
+
+    // Add any other options passed in
+    for (let n in options) {
+      if ('scope' === n) {
+        mapCommandHash[n] = processScope(options[n]);
+      } else {
+        // Only include if not in exclusion list
+        if (exclusionList.indexOf(n) === -1) {
+          mapCommandHash[n] = options[n];
+        }
+      }
+    }
+
+    options = Object.assign({}, options);
+
+    // Ensure we have the right read preference inheritance
+    options.readPreference = ReadPreference.resolve(coll, options);
+
+    // If we have a read preference and inline is not set as output fail hard
+    if (
+      options.readPreference !== false &&
+      options.readPreference !== 'primary' &&
+      options['out'] &&
+      options['out'].inline !== 1 &&
+      options['out'] !== 'inline'
+    ) {
+      // Force readPreference to primary
+      options.readPreference = 'primary';
+      // Decorate command with writeConcern if supported
+      applyWriteConcern(mapCommandHash, { db: coll.s.db, collection: coll }, options);
+    } else {
+      decorateWithReadConcern(mapCommandHash, coll, options);
+    }
+
+    // Is bypassDocumentValidation specified
+    if (options.bypassDocumentValidation === true) {
+      mapCommandHash.bypassDocumentValidation = options.bypassDocumentValidation;
+    }
+
+    // Have we specified collation
+    try {
+      decorateWithCollation(mapCommandHash, coll, options);
+    } catch (err) {
+      return callback(err, null);
+    }
+
+    // Execute command
+    executeCommand(coll.s.db, mapCommandHash, options, (err, result) => {
+      if (err) return handleCallback(callback, err);
+      // Check if we have an error
+      if (1 !== result.ok || result.err || result.errmsg) {
+        return handleCallback(callback, toError(result));
+      }
+
+      // Create statistics value
+      const stats = {};
+      if (result.timeMillis) stats['processtime'] = result.timeMillis;
+      if (result.counts) stats['counts'] = result.counts;
+      if (result.timing) stats['timing'] = result.timing;
+
+      // invoked with inline?
+      if (result.results) {
+        // If we wish for no verbosity
+        if (options['verbose'] == null || !options['verbose']) {
+          return handleCallback(callback, null, result.results);
+        }
+
+        return handleCallback(callback, null, { results: result.results, stats: stats });
+      }
+
+      // The returned collection
+      let collection = null;
+
+      // If we have an object it's a different db
+      if (result.result != null && typeof result.result === 'object') {
+        const doc = result.result;
+        // Return a collection from another db
+        let Db = loadDb();
+        collection = new Db(doc.db, coll.s.db.s.topology, coll.s.db.s.options).collection(
+          doc.collection
+        );
+      } else {
+        // Create a collection object that wraps the result collection
+        collection = coll.s.db.collection(result.result);
+      }
+
+      // If we wish for no verbosity
+      if (options['verbose'] == null || !options['verbose']) {
+        return handleCallback(callback, err, collection);
+      }
+
+      // Return stats as third set of values
+      handleCallback(callback, err, { collection: collection, stats: stats });
+    });
+  }
+}
+
+/**
+ * Functions that are passed as scope args must
+ * be converted to Code instances.
+ * @ignore
+ */
+function processScope(scope) {
+  if (!isObject(scope) || scope._bsontype === 'ObjectID') {
+    return scope;
+  }
+
+  const keys = Object.keys(scope);
+  let key;
+  const new_scope = {};
+
+  for (let i = keys.length - 1; i >= 0; i--) {
+    key = keys[i];
+    if ('function' === typeof scope[key]) {
+      new_scope[key] = new Code(String(scope[key]));
+    } else {
+      new_scope[key] = processScope(scope[key]);
+    }
+  }
+
+  return new_scope;
+}
+
+module.exports = MapReduceOperation;
diff --git a/node_modules/mongodb/lib/operations/operation.js b/node_modules/mongodb/lib/operations/operation.js
new file mode 100644
index 0000000..28a9d05
--- /dev/null
+++ b/node_modules/mongodb/lib/operations/operation.js
@@ -0,0 +1,66 @@
+'use strict';
+
+const Aspect = {
+  READ_OPERATION: Symbol('READ_OPERATION'),
+  WRITE_OPERATION: Symbol('WRITE_OPERATION'),
+  RETRYABLE: Symbol('RETRYABLE'),
+  EXECUTE_WITH_SELECTION: Symbol('EXECUTE_WITH_SELECTION'),
+  NO_INHERIT_OPTIONS: Symbol('NO_INHERIT_OPTIONS')
+};
+
+/**
+ * This class acts as a parent class for any operation and is responsible for setting this.options,
+ * as well as setting and getting a session.
+ * Additionally, this class implements `hasAspect`, which determines whether an operation has
+ * a specific aspect.
+ */
+class OperationBase {
+  constructor(options) {
+    this.options = Object.assign({}, options);
+  }
+
+  hasAspect(aspect) {
+    if (this.constructor.aspects == null) {
+      return false;
+    }
+    return this.constructor.aspects.has(aspect);
+  }
+
+  set session(session) {
+    Object.assign(this.options, { session });
+  }
+
+  get session() {
+    return this.options.session;
+  }
+
+  clearSession() {
+    delete this.options.session;
+  }
+
+  get canRetryRead() {
+    return true;
+  }
+
+  execute() {
+    throw new TypeError('`execute` must be implemented for OperationBase subclasses');
+  }
+}
+
+function defineAspects(operation, aspects) {
+  if (!Array.isArray(aspects) && !(aspects instanceof Set)) {
+    aspects = [aspects];
+  }
+  aspects = new Set(aspects);
+  Object.defineProperty(operation, 'aspects', {
+    value: aspects,
+    writable: false
+  });
+  return aspects;
+}
+
+module.exports = {
+  Aspect,
+  defineAspects,
+  OperationBase
+};
diff --git a/node_modules/mongodb/lib/operations/options_operation.js b/node_modules/mongodb/lib/operations/options_operation.js
new file mode 100644
index 0000000..9a739a5
--- /dev/null
+++ b/node_modules/mongodb/lib/operations/options_operation.js
@@ -0,0 +1,32 @@
+'use strict';
+
+const OperationBase = require('./operation').OperationBase;
+const handleCallback = require('../utils').handleCallback;
+const MongoError = require('../core').MongoError;
+
+class OptionsOperation extends OperationBase {
+  constructor(collection, options) {
+    super(options);
+
+    this.collection = collection;
+  }
+
+  execute(callback) {
+    const coll = this.collection;
+    const opts = this.options;
+
+    coll.s.db.listCollections({ name: coll.collectionName }, opts).toArray((err, collections) => {
+      if (err) return handleCallback(callback, err);
+      if (collections.length === 0) {
+        return handleCallback(
+          callback,
+          MongoError.create({ message: `collection ${coll.namespace} not found`, driver: true })
+        );
+      }
+
+      handleCallback(callback, err, collections[0].options || null);
+    });
+  }
+}
+
+module.exports = OptionsOperation;
diff --git a/node_modules/mongodb/lib/operations/profiling_level.js b/node_modules/mongodb/lib/operations/profiling_level.js
new file mode 100644
index 0000000..3f7639b
--- /dev/null
+++ b/node_modules/mongodb/lib/operations/profiling_level.js
@@ -0,0 +1,31 @@
+'use strict';
+
+const CommandOperation = require('./command');
+
+class ProfilingLevelOperation extends CommandOperation {
+  constructor(db, command, options) {
+    super(db, options);
+  }
+
+  _buildCommand() {
+    const command = { profile: -1 };
+
+    return command;
+  }
+
+  execute(callback) {
+    super.execute((err, doc) => {
+      if (err == null && doc.ok === 1) {
+        const was = doc.was;
+        if (was === 0) return callback(null, 'off');
+        if (was === 1) return callback(null, 'slow_only');
+        if (was === 2) return callback(null, 'all');
+        return callback(new Error('Error: illegal profiling level value ' + was), null);
+      } else {
+        err != null ? callback(err, null) : callback(new Error('Error with profile command'), null);
+      }
+    });
+  }
+}
+
+module.exports = ProfilingLevelOperation;
diff --git a/node_modules/mongodb/lib/operations/re_index.js b/node_modules/mongodb/lib/operations/re_index.js
new file mode 100644
index 0000000..dc44522
--- /dev/null
+++ b/node_modules/mongodb/lib/operations/re_index.js
@@ -0,0 +1,33 @@
+'use strict';
+
+const Aspect = require('./operation').Aspect;
+const defineAspects = require('./operation').defineAspects;
+const CommandOperationV2 = require('./command_v2');
+const serverType = require('../core/sdam/common').serverType;
+const ServerType = require('../core/sdam/common').ServerType;
+const MongoError = require('../core').MongoError;
+
+class ReIndexOperation extends CommandOperationV2 {
+  constructor(collection, options) {
+    super(collection, options);
+    this.collectionName = collection.collectionName;
+  }
+
+  execute(server, callback) {
+    if (serverType(server) !== ServerType.Standalone) {
+      callback(new MongoError(`reIndex can only be executed on standalone servers.`));
+      return;
+    }
+    super.executeCommand(server, { reIndex: this.collectionName }, (err, result) => {
+      if (err) {
+        callback(err);
+        return;
+      }
+      callback(null, !!result.ok);
+    });
+  }
+}
+
+defineAspects(ReIndexOperation, [Aspect.EXECUTE_WITH_SELECTION]);
+
+module.exports = ReIndexOperation;
diff --git a/node_modules/mongodb/lib/operations/remove_user.js b/node_modules/mongodb/lib/operations/remove_user.js
new file mode 100644
index 0000000..9e8376b
--- /dev/null
+++ b/node_modules/mongodb/lib/operations/remove_user.js
@@ -0,0 +1,52 @@
+'use strict';
+
+const Aspect = require('./operation').Aspect;
+const CommandOperation = require('./command');
+const defineAspects = require('./operation').defineAspects;
+const handleCallback = require('../utils').handleCallback;
+const WriteConcern = require('../write_concern');
+
+class RemoveUserOperation extends CommandOperation {
+  constructor(db, username, options) {
+    const commandOptions = {};
+
+    const writeConcern = WriteConcern.fromOptions(options);
+    if (writeConcern != null) {
+      commandOptions.writeConcern = writeConcern;
+    }
+
+    if (options.dbName) {
+      commandOptions.dbName = options.dbName;
+    }
+
+    // Add maxTimeMS to options if set
+    if (typeof options.maxTimeMS === 'number') {
+      commandOptions.maxTimeMS = options.maxTimeMS;
+    }
+
+    super(db, commandOptions);
+
+    this.username = username;
+  }
+
+  _buildCommand() {
+    const username = this.username;
+
+    // Build the command to execute
+    const command = { dropUser: username };
+
+    return command;
+  }
+
+  execute(callback) {
+    // Attempt to execute command
+    super.execute((err, result) => {
+      if (err) return handleCallback(callback, err, null);
+      handleCallback(callback, err, result.ok ? true : false);
+    });
+  }
+}
+
+defineAspects(RemoveUserOperation, Aspect.WRITE_OPERATION);
+
+module.exports = RemoveUserOperation;
diff --git a/node_modules/mongodb/lib/operations/rename.js b/node_modules/mongodb/lib/operations/rename.js
new file mode 100644
index 0000000..8098fe6
--- /dev/null
+++ b/node_modules/mongodb/lib/operations/rename.js
@@ -0,0 +1,61 @@
+'use strict';
+
+const OperationBase = require('./operation').OperationBase;
+const applyWriteConcern = require('../utils').applyWriteConcern;
+const checkCollectionName = require('../utils').checkCollectionName;
+const executeDbAdminCommand = require('./db_ops').executeDbAdminCommand;
+const handleCallback = require('../utils').handleCallback;
+const loadCollection = require('../dynamic_loaders').loadCollection;
+const toError = require('../utils').toError;
+
+class RenameOperation extends OperationBase {
+  constructor(collection, newName, options) {
+    super(options);
+
+    this.collection = collection;
+    this.newName = newName;
+  }
+
+  execute(callback) {
+    const coll = this.collection;
+    const newName = this.newName;
+    const options = this.options;
+
+    let Collection = loadCollection();
+    // Check the collection name
+    checkCollectionName(newName);
+    // Build the command
+    const renameCollection = coll.namespace;
+    const toCollection = coll.s.namespace.withCollection(newName).toString();
+    const dropTarget = typeof options.dropTarget === 'boolean' ? options.dropTarget : false;
+    const cmd = { renameCollection: renameCollection, to: toCollection, dropTarget: dropTarget };
+
+    // Decorate command with writeConcern if supported
+    applyWriteConcern(cmd, { db: coll.s.db, collection: coll }, options);
+
+    // Execute against admin
+    executeDbAdminCommand(coll.s.db.admin().s.db, cmd, options, (err, doc) => {
+      if (err) return handleCallback(callback, err, null);
+      // We have an error
+      if (doc.errmsg) return handleCallback(callback, toError(doc), null);
+      try {
+        return handleCallback(
+          callback,
+          null,
+          new Collection(
+            coll.s.db,
+            coll.s.topology,
+            coll.s.namespace.db,
+            newName,
+            coll.s.pkFactory,
+            coll.s.options
+          )
+        );
+      } catch (err) {
+        return handleCallback(callback, toError(err), null);
+      }
+    });
+  }
+}
+
+module.exports = RenameOperation;
diff --git a/node_modules/mongodb/lib/operations/replace_one.js b/node_modules/mongodb/lib/operations/replace_one.js
new file mode 100644
index 0000000..93ec0ef
--- /dev/null
+++ b/node_modules/mongodb/lib/operations/replace_one.js
@@ -0,0 +1,54 @@
+'use strict';
+
+const OperationBase = require('./operation').OperationBase;
+const updateDocuments = require('./common_functions').updateDocuments;
+const hasAtomicOperators = require('../utils').hasAtomicOperators;
+
+class ReplaceOneOperation extends OperationBase {
+  constructor(collection, filter, replacement, options) {
+    super(options);
+
+    if (hasAtomicOperators(replacement)) {
+      throw new TypeError('Replacement document must not contain atomic operators');
+    }
+
+    this.collection = collection;
+    this.filter = filter;
+    this.replacement = replacement;
+  }
+
+  execute(callback) {
+    const coll = this.collection;
+    const filter = this.filter;
+    const replacement = this.replacement;
+    const options = this.options;
+
+    // Set single document update
+    options.multi = false;
+
+    // Execute update
+    updateDocuments(coll, filter, replacement, options, (err, r) =>
+      replaceCallback(err, r, replacement, callback)
+    );
+  }
+}
+
+function replaceCallback(err, r, doc, callback) {
+  if (callback == null) return;
+  if (err && callback) return callback(err);
+  if (r == null) return callback(null, { result: { ok: 1 } });
+
+  r.modifiedCount = r.result.nModified != null ? r.result.nModified : r.result.n;
+  r.upsertedId =
+    Array.isArray(r.result.upserted) && r.result.upserted.length > 0
+      ? r.result.upserted[0] // FIXME(major): should be `r.result.upserted[0]._id`
+      : null;
+  r.upsertedCount =
+    Array.isArray(r.result.upserted) && r.result.upserted.length ? r.result.upserted.length : 0;
+  r.matchedCount =
+    Array.isArray(r.result.upserted) && r.result.upserted.length > 0 ? 0 : r.result.n;
+  r.ops = [doc]; // TODO: Should we still have this?
+  if (callback) callback(null, r);
+}
+
+module.exports = ReplaceOneOperation;
diff --git a/node_modules/mongodb/lib/operations/run_command.js b/node_modules/mongodb/lib/operations/run_command.js
new file mode 100644
index 0000000..5525ba2
--- /dev/null
+++ b/node_modules/mongodb/lib/operations/run_command.js
@@ -0,0 +1,19 @@
+'use strict';
+
+const CommandOperationV2 = require('./command_v2');
+const defineAspects = require('./operation').defineAspects;
+const Aspect = require('./operation').Aspect;
+
+class RunCommandOperation extends CommandOperationV2 {
+  constructor(parent, command, options) {
+    super(parent, options);
+    this.command = command;
+  }
+  execute(server, callback) {
+    const command = this.command;
+    this.executeCommand(server, command, callback);
+  }
+}
+defineAspects(RunCommandOperation, [Aspect.EXECUTE_WITH_SELECTION, Aspect.NO_INHERIT_OPTIONS]);
+
+module.exports = RunCommandOperation;
diff --git a/node_modules/mongodb/lib/operations/set_profiling_level.js b/node_modules/mongodb/lib/operations/set_profiling_level.js
new file mode 100644
index 0000000..b31cc13
--- /dev/null
+++ b/node_modules/mongodb/lib/operations/set_profiling_level.js
@@ -0,0 +1,48 @@
+'use strict';
+
+const CommandOperation = require('./command');
+const levelValues = new Set(['off', 'slow_only', 'all']);
+
+class SetProfilingLevelOperation extends CommandOperation {
+  constructor(db, level, options) {
+    let profile = 0;
+
+    if (level === 'off') {
+      profile = 0;
+    } else if (level === 'slow_only') {
+      profile = 1;
+    } else if (level === 'all') {
+      profile = 2;
+    }
+
+    super(db, options);
+    this.level = level;
+    this.profile = profile;
+  }
+
+  _buildCommand() {
+    const profile = this.profile;
+
+    // Set up the profile number
+    const command = { profile };
+
+    return command;
+  }
+
+  execute(callback) {
+    const level = this.level;
+
+    if (!levelValues.has(level)) {
+      return callback(new Error('Error: illegal profiling level value ' + level));
+    }
+
+    super.execute((err, doc) => {
+      if (err == null && doc.ok === 1) return callback(null, level);
+      return err != null
+        ? callback(err, null)
+        : callback(new Error('Error with profile command'), null);
+    });
+  }
+}
+
+module.exports = SetProfilingLevelOperation;
diff --git a/node_modules/mongodb/lib/operations/stats.js b/node_modules/mongodb/lib/operations/stats.js
new file mode 100644
index 0000000..ff79126
--- /dev/null
+++ b/node_modules/mongodb/lib/operations/stats.js
@@ -0,0 +1,45 @@
+'use strict';
+
+const Aspect = require('./operation').Aspect;
+const CommandOperation = require('./command');
+const defineAspects = require('./operation').defineAspects;
+
+/**
+ * Get all the collection statistics.
+ *
+ * @class
+ * @property {Collection} a Collection instance.
+ * @property {object} [options] Optional settings. See Collection.prototype.stats for a list of options.
+ */
+class StatsOperation extends CommandOperation {
+  /**
+   * Construct a Stats operation.
+   *
+   * @param {Collection} a Collection instance.
+   * @param {object} [options] Optional settings. See Collection.prototype.stats for a list of options.
+   */
+  constructor(collection, options) {
+    super(collection.s.db, options, collection);
+  }
+
+  _buildCommand() {
+    const collection = this.collection;
+    const options = this.options;
+
+    // Build command object
+    const command = {
+      collStats: collection.collectionName
+    };
+
+    // Check if we have the scale value
+    if (options['scale'] != null) {
+      command['scale'] = options['scale'];
+    }
+
+    return command;
+  }
+}
+
+defineAspects(StatsOperation, Aspect.READ_OPERATION);
+
+module.exports = StatsOperation;
diff --git a/node_modules/mongodb/lib/operations/update_many.js b/node_modules/mongodb/lib/operations/update_many.js
new file mode 100644
index 0000000..725ed28
--- /dev/null
+++ b/node_modules/mongodb/lib/operations/update_many.js
@@ -0,0 +1,34 @@
+'use strict';
+
+const OperationBase = require('./operation').OperationBase;
+const updateCallback = require('./common_functions').updateCallback;
+const updateDocuments = require('./common_functions').updateDocuments;
+const hasAtomicOperators = require('../utils').hasAtomicOperators;
+
+class UpdateManyOperation extends OperationBase {
+  constructor(collection, filter, update, options) {
+    super(options);
+
+    if (!hasAtomicOperators(update)) {
+      throw new TypeError('Update document requires atomic operators');
+    }
+
+    this.collection = collection;
+    this.filter = filter;
+    this.update = update;
+  }
+
+  execute(callback) {
+    const coll = this.collection;
+    const filter = this.filter;
+    const update = this.update;
+    const options = this.options;
+
+    // Set single document update
+    options.multi = true;
+    // Execute update
+    updateDocuments(coll, filter, update, options, (err, r) => updateCallback(err, r, callback));
+  }
+}
+
+module.exports = UpdateManyOperation;
diff --git a/node_modules/mongodb/lib/operations/update_one.js b/node_modules/mongodb/lib/operations/update_one.js
new file mode 100644
index 0000000..eea12a8
--- /dev/null
+++ b/node_modules/mongodb/lib/operations/update_one.js
@@ -0,0 +1,49 @@
+'use strict';
+
+const OperationBase = require('./operation').OperationBase;
+const updateDocuments = require('./common_functions').updateDocuments;
+const hasAtomicOperators = require('../utils').hasAtomicOperators;
+
+class UpdateOneOperation extends OperationBase {
+  constructor(collection, filter, update, options) {
+    super(options);
+
+    if (!hasAtomicOperators(update)) {
+      throw new TypeError('Update document requires atomic operators');
+    }
+
+    this.collection = collection;
+    this.filter = filter;
+    this.update = update;
+  }
+
+  execute(callback) {
+    const coll = this.collection;
+    const filter = this.filter;
+    const update = this.update;
+    const options = this.options;
+
+    // Set single document update
+    options.multi = false;
+    // Execute update
+    updateDocuments(coll, filter, update, options, (err, r) => updateCallback(err, r, callback));
+  }
+}
+
+function updateCallback(err, r, callback) {
+  if (callback == null) return;
+  if (err) return callback(err);
+  if (r == null) return callback(null, { result: { ok: 1 } });
+  r.modifiedCount = r.result.nModified != null ? r.result.nModified : r.result.n;
+  r.upsertedId =
+    Array.isArray(r.result.upserted) && r.result.upserted.length > 0
+      ? r.result.upserted[0] // FIXME(major): should be `r.result.upserted[0]._id`
+      : null;
+  r.upsertedCount =
+    Array.isArray(r.result.upserted) && r.result.upserted.length ? r.result.upserted.length : 0;
+  r.matchedCount =
+    Array.isArray(r.result.upserted) && r.result.upserted.length > 0 ? 0 : r.result.n;
+  callback(null, r);
+}
+
+module.exports = UpdateOneOperation;
diff --git a/node_modules/mongodb/lib/operations/validate_collection.js b/node_modules/mongodb/lib/operations/validate_collection.js
new file mode 100644
index 0000000..bc16cd2
--- /dev/null
+++ b/node_modules/mongodb/lib/operations/validate_collection.js
@@ -0,0 +1,39 @@
+'use strict';
+
+const CommandOperation = require('./command');
+
+class ValidateCollectionOperation extends CommandOperation {
+  constructor(admin, collectionName, options) {
+    // Decorate command with extra options
+    let command = { validate: collectionName };
+    const keys = Object.keys(options);
+    for (let i = 0; i < keys.length; i++) {
+      if (Object.prototype.hasOwnProperty.call(options, keys[i]) && keys[i] !== 'session') {
+        command[keys[i]] = options[keys[i]];
+      }
+    }
+
+    super(admin.s.db, options, null, command);
+    this.collectionName = collectionName;
+  }
+
+  execute(callback) {
+    const collectionName = this.collectionName;
+
+    super.execute((err, doc) => {
+      if (err != null) return callback(err, null);
+
+      if (doc.ok === 0) return callback(new Error('Error with validate command'), null);
+      if (doc.result != null && doc.result.constructor !== String)
+        return callback(new Error('Error with validation data'), null);
+      if (doc.result != null && doc.result.match(/exception|corrupt/) != null)
+        return callback(new Error('Error: invalid collection ' + collectionName), null);
+      if (doc.valid != null && !doc.valid)
+        return callback(new Error('Error: invalid collection ' + collectionName), null);
+
+      return callback(null, doc);
+    });
+  }
+}
+
+module.exports = ValidateCollectionOperation;