api, login, auth

1 files changed, 1162 insertions, 0 deletions

diff --git a/node_modules/mongoose/lib/aggregate.js b/node_modules/mongoose/lib/aggregate.js
new file mode 100644
index 0000000..f562e57
--- /dev/null
+++ b/node_modules/mongoose/lib/aggregate.js
@@ -0,0 +1,1162 @@
+'use strict';
+
+/*!
+ * Module dependencies
+ */
+
+const AggregationCursor = require('./cursor/AggregationCursor');
+const Query = require('./query');
+const applyGlobalMaxTimeMS = require('./helpers/query/applyGlobalMaxTimeMS');
+const promiseOrCallback = require('./helpers/promiseOrCallback');
+const stringifyAccumulatorOptions = require('./helpers/aggregate/stringifyAccumulatorOptions');
+const util = require('util');
+const utils = require('./utils');
+const read = Query.prototype.read;
+const readConcern = Query.prototype.readConcern;
+
+/**
+ * Aggregate constructor used for building aggregation pipelines. Do not
+ * instantiate this class directly, use [Model.aggregate()](/docs/api.html#model_Model.aggregate) instead.
+ *
+ * ####Example:
+ *
+ *     const aggregate = Model.aggregate([
+ *       { $project: { a: 1, b: 1 } },
+ *       { $skip: 5 }
+ *     ]);
+ *
+ *     Model.
+ *       aggregate([{ $match: { age: { $gte: 21 }}}]).
+ *       unwind('tags').
+ *       exec(callback);
+ *
+ * ####Note:
+ *
+ * - The documents returned are plain javascript objects, not mongoose documents (since any shape of document can be returned).
+ * - Mongoose does **not** cast pipeline stages. The below will **not** work unless `_id` is a string in the database
+ *
+ * ```javascript
+ *   new Aggregate([{ $match: { _id: '00000000000000000000000a' } }]);
+ *   // Do this instead to cast to an ObjectId
+ *   new Aggregate([{ $match: { _id: mongoose.Types.ObjectId('00000000000000000000000a') } }]);
+ * ```
+ *
+ * @see MongoDB http://docs.mongodb.org/manual/applications/aggregation/
+ * @see driver http://mongodb.github.com/node-mongodb-native/api-generated/collection.html#aggregate
+ * @param {Array} [pipeline] aggregation pipeline as an array of objects
+ * @api public
+ */
+
+function Aggregate(pipeline) {
+  this._pipeline = [];
+  this._model = undefined;
+  this.options = {};
+
+  if (arguments.length === 1 && util.isArray(pipeline)) {
+    this.append.apply(this, pipeline);
+  }
+}
+
+/**
+ * Contains options passed down to the [aggregate command](https://docs.mongodb.com/manual/reference/command/aggregate/).
+ * Supported options are:
+ *
+ * - `readPreference`
+ * - [`cursor`](./api.html#aggregate_Aggregate-cursor)
+ * - [`explain`](./api.html#aggregate_Aggregate-explain)
+ * - [`allowDiskUse`](./api.html#aggregate_Aggregate-allowDiskUse)
+ * - `maxTimeMS`
+ * - `bypassDocumentValidation`
+ * - `raw`
+ * - `promoteLongs`
+ * - `promoteValues`
+ * - `promoteBuffers`
+ * - [`collation`](./api.html#aggregate_Aggregate-collation)
+ * - `comment`
+ * - [`session`](./api.html#aggregate_Aggregate-session)
+ *
+ * @property options
+ * @memberOf Aggregate
+ * @api public
+ */
+
+Aggregate.prototype.options;
+
+/**
+ * Get/set the model that this aggregation will execute on.
+ *
+ * ####Example:
+ *     const aggregate = MyModel.aggregate([{ $match: { answer: 42 } }]);
+ *     aggregate.model() === MyModel; // true
+ *
+ *     // Change the model. There's rarely any reason to do this.
+ *     aggregate.model(SomeOtherModel);
+ *     aggregate.model() === SomeOtherModel; // true
+ *
+ * @param {Model} [model] the model to which the aggregate is to be bound
+ * @return {Aggregate|Model} if model is passed, will return `this`, otherwise will return the model
+ * @api public
+ */
+
+Aggregate.prototype.model = function(model) {
+  if (arguments.length === 0) {
+    return this._model;
+  }
+
+  this._model = model;
+  if (model.schema != null) {
+    if (this.options.readPreference == null &&
+        model.schema.options.read != null) {
+      this.options.readPreference = model.schema.options.read;
+    }
+    if (this.options.collation == null &&
+        model.schema.options.collation != null) {
+      this.options.collation = model.schema.options.collation;
+    }
+  }
+  return this;
+};
+
+/**
+ * Appends new operators to this aggregate pipeline
+ *
+ * ####Examples:
+ *
+ *     aggregate.append({ $project: { field: 1 }}, { $limit: 2 });
+ *
+ *     // or pass an array
+ *     const pipeline = [{ $match: { daw: 'Logic Audio X' }} ];
+ *     aggregate.append(pipeline);
+ *
+ * @param {Object} ops operator(s) to append
+ * @return {Aggregate}
+ * @api public
+ */
+
+Aggregate.prototype.append = function() {
+  const args = (arguments.length === 1 && util.isArray(arguments[0]))
+    ? arguments[0]
+    : utils.args(arguments);
+
+  if (!args.every(isOperator)) {
+    throw new Error('Arguments must be aggregate pipeline operators');
+  }
+
+  this._pipeline = this._pipeline.concat(args);
+
+  return this;
+};
+
+/**
+ * Appends a new $addFields operator to this aggregate pipeline.
+ * Requires MongoDB v3.4+ to work
+ *
+ * ####Examples:
+  *
+ *     // adding new fields based on existing fields
+ *     aggregate.addFields({
+ *         newField: '$b.nested'
+ *       , plusTen: { $add: ['$val', 10]}
+ *       , sub: {
+ *            name: '$a'
+ *         }
+ *     })
+ *
+ *     // etc
+ *     aggregate.addFields({ salary_k: { $divide: [ "$salary", 1000 ] } });
+ *
+ * @param {Object} arg field specification
+ * @see $addFields https://docs.mongodb.com/manual/reference/operator/aggregation/addFields/
+ * @return {Aggregate}
+ * @api public
+ */
+Aggregate.prototype.addFields = function(arg) {
+  const fields = {};
+  if (typeof arg === 'object' && !util.isArray(arg)) {
+    Object.keys(arg).forEach(function(field) {
+      fields[field] = arg[field];
+    });
+  } else {
+    throw new Error('Invalid addFields() argument. Must be an object');
+  }
+  return this.append({ $addFields: fields });
+};
+
+/**
+ * Appends a new $project operator to this aggregate pipeline.
+ *
+ * Mongoose query [selection syntax](#query_Query-select) is also supported.
+ *
+ * ####Examples:
+ *
+ *     // include a, include b, exclude _id
+ *     aggregate.project("a b -_id");
+ *
+ *     // or you may use object notation, useful when
+ *     // you have keys already prefixed with a "-"
+ *     aggregate.project({a: 1, b: 1, _id: 0});
+ *
+ *     // reshaping documents
+ *     aggregate.project({
+ *         newField: '$b.nested'
+ *       , plusTen: { $add: ['$val', 10]}
+ *       , sub: {
+ *            name: '$a'
+ *         }
+ *     })
+ *
+ *     // etc
+ *     aggregate.project({ salary_k: { $divide: [ "$salary", 1000 ] } });
+ *
+ * @param {Object|String} arg field specification
+ * @see projection http://docs.mongodb.org/manual/reference/aggregation/project/
+ * @return {Aggregate}
+ * @api public
+ */
+
+Aggregate.prototype.project = function(arg) {
+  const fields = {};
+
+  if (typeof arg === 'object' && !util.isArray(arg)) {
+    Object.keys(arg).forEach(function(field) {
+      fields[field] = arg[field];
+    });
+  } else if (arguments.length === 1 && typeof arg === 'string') {
+    arg.split(/\s+/).forEach(function(field) {
+      if (!field) {
+        return;
+      }
+      const include = field[0] === '-' ? 0 : 1;
+      if (include === 0) {
+        field = field.substring(1);
+      }
+      fields[field] = include;
+    });
+  } else {
+    throw new Error('Invalid project() argument. Must be string or object');
+  }
+
+  return this.append({ $project: fields });
+};
+
+/**
+ * Appends a new custom $group operator to this aggregate pipeline.
+ *
+ * ####Examples:
+ *
+ *     aggregate.group({ _id: "$department" });
+ *
+ * @see $group http://docs.mongodb.org/manual/reference/aggregation/group/
+ * @method group
+ * @memberOf Aggregate
+ * @instance
+ * @param {Object} arg $group operator contents
+ * @return {Aggregate}
+ * @api public
+ */
+
+/**
+ * Appends a new custom $match operator to this aggregate pipeline.
+ *
+ * ####Examples:
+ *
+ *     aggregate.match({ department: { $in: [ "sales", "engineering" ] } });
+ *
+ * @see $match http://docs.mongodb.org/manual/reference/aggregation/match/
+ * @method match
+ * @memberOf Aggregate
+ * @instance
+ * @param {Object} arg $match operator contents
+ * @return {Aggregate}
+ * @api public
+ */
+
+/**
+ * Appends a new $skip operator to this aggregate pipeline.
+ *
+ * ####Examples:
+ *
+ *     aggregate.skip(10);
+ *
+ * @see $skip http://docs.mongodb.org/manual/reference/aggregation/skip/
+ * @method skip
+ * @memberOf Aggregate
+ * @instance
+ * @param {Number} num number of records to skip before next stage
+ * @return {Aggregate}
+ * @api public
+ */
+
+/**
+ * Appends a new $limit operator to this aggregate pipeline.
+ *
+ * ####Examples:
+ *
+ *     aggregate.limit(10);
+ *
+ * @see $limit http://docs.mongodb.org/manual/reference/aggregation/limit/
+ * @method limit
+ * @memberOf Aggregate
+ * @instance
+ * @param {Number} num maximum number of records to pass to the next stage
+ * @return {Aggregate}
+ * @api public
+ */
+
+/**
+ * Appends a new $geoNear operator to this aggregate pipeline.
+ *
+ * ####NOTE:
+ *
+ * **MUST** be used as the first operator in the pipeline.
+ *
+ * ####Examples:
+ *
+ *     aggregate.near({
+ *       near: [40.724, -73.997],
+ *       distanceField: "dist.calculated", // required
+ *       maxDistance: 0.008,
+ *       query: { type: "public" },
+ *       includeLocs: "dist.location",
+ *       uniqueDocs: true,
+ *       num: 5
+ *     });
+ *
+ * @see $geoNear http://docs.mongodb.org/manual/reference/aggregation/geoNear/
+ * @method near
+ * @memberOf Aggregate
+ * @instance
+ * @param {Object} arg
+ * @return {Aggregate}
+ * @api public
+ */
+
+Aggregate.prototype.near = function(arg) {
+  const op = {};
+  op.$geoNear = arg;
+  return this.append(op);
+};
+
+/*!
+ * define methods
+ */
+
+'group match skip limit out'.split(' ').forEach(function($operator) {
+  Aggregate.prototype[$operator] = function(arg) {
+    const op = {};
+    op['$' + $operator] = arg;
+    return this.append(op);
+  };
+});
+
+/**
+ * Appends new custom $unwind operator(s) to this aggregate pipeline.
+ *
+ * Note that the `$unwind` operator requires the path name to start with '$'.
+ * Mongoose will prepend '$' if the specified field doesn't start '$'.
+ *
+ * ####Examples:
+ *
+ *     aggregate.unwind("tags");
+ *     aggregate.unwind("a", "b", "c");
+ *     aggregate.unwind({ path: '$tags', preserveNullAndEmptyArrays: true });
+ *
+ * @see $unwind http://docs.mongodb.org/manual/reference/aggregation/unwind/
+ * @param {String|Object} fields the field(s) to unwind, either as field names or as [objects with options](https://docs.mongodb.com/manual/reference/operator/aggregation/unwind/#document-operand-with-options). If passing a string, prefixing the field name with '$' is optional. If passing an object, `path` must start with '$'.
+ * @return {Aggregate}
+ * @api public
+ */
+
+Aggregate.prototype.unwind = function() {
+  const args = utils.args(arguments);
+
+  const res = [];
+  for (const arg of args) {
+    if (arg && typeof arg === 'object') {
+      res.push({ $unwind: arg });
+    } else if (typeof arg === 'string') {
+      res.push({
+        $unwind: (arg && arg.startsWith('$')) ? arg : '$' + arg
+      });
+    } else {
+      throw new Error('Invalid arg "' + arg + '" to unwind(), ' +
+        'must be string or object');
+    }
+  }
+
+  return this.append.apply(this, res);
+};
+
+/**
+ * Appends a new $replaceRoot operator to this aggregate pipeline.
+ *
+ * Note that the `$replaceRoot` operator requires field strings to start with '$'.
+ * If you are passing in a string Mongoose will prepend '$' if the specified field doesn't start '$'.
+ * If you are passing in an object the strings in your expression will not be altered.
+ *
+ * ####Examples:
+ *
+ *     aggregate.replaceRoot("user");
+ *
+ *     aggregate.replaceRoot({ x: { $concat: ['$this', '$that'] } });
+ *
+ * @see $replaceRoot https://docs.mongodb.org/manual/reference/operator/aggregation/replaceRoot
+ * @param {String|Object} the field or document which will become the new root document
+ * @return {Aggregate}
+ * @api public
+ */
+
+Aggregate.prototype.replaceRoot = function(newRoot) {
+  let ret;
+
+  if (typeof newRoot === 'string') {
+    ret = newRoot.startsWith('$') ? newRoot : '$' + newRoot;
+  } else {
+    ret = newRoot;
+  }
+
+  return this.append({
+    $replaceRoot: {
+      newRoot: ret
+    }
+  });
+};
+
+/**
+ * Appends a new $count operator to this aggregate pipeline.
+ *
+ * ####Examples:
+ *
+ *     aggregate.count("userCount");
+ *
+ * @see $count https://docs.mongodb.org/manual/reference/operator/aggregation/count
+ * @param {String} the name of the count field
+ * @return {Aggregate}
+ * @api public
+ */
+
+Aggregate.prototype.count = function(countName) {
+  return this.append({ $count: countName });
+};
+
+/**
+ * Appends a new $sortByCount operator to this aggregate pipeline. Accepts either a string field name
+ * or a pipeline object.
+ *
+ * Note that the `$sortByCount` operator requires the new root to start with '$'.
+ * Mongoose will prepend '$' if the specified field name doesn't start with '$'.
+ *
+ * ####Examples:
+ *
+ *     aggregate.sortByCount('users');
+ *     aggregate.sortByCount({ $mergeObjects: [ "$employee", "$business" ] })
+ *
+ * @see $sortByCount https://docs.mongodb.com/manual/reference/operator/aggregation/sortByCount/
+ * @param {Object|String} arg
+ * @return {Aggregate} this
+ * @api public
+ */
+
+Aggregate.prototype.sortByCount = function(arg) {
+  if (arg && typeof arg === 'object') {
+    return this.append({ $sortByCount: arg });
+  } else if (typeof arg === 'string') {
+    return this.append({
+      $sortByCount: (arg && arg.startsWith('$')) ? arg : '$' + arg
+    });
+  } else {
+    throw new TypeError('Invalid arg "' + arg + '" to sortByCount(), ' +
+      'must be string or object');
+  }
+};
+
+/**
+ * Appends new custom $lookup operator(s) to this aggregate pipeline.
+ *
+ * ####Examples:
+ *
+ *     aggregate.lookup({ from: 'users', localField: 'userId', foreignField: '_id', as: 'users' });
+ *
+ * @see $lookup https://docs.mongodb.org/manual/reference/operator/aggregation/lookup/#pipe._S_lookup
+ * @param {Object} options to $lookup as described in the above link
+ * @return {Aggregate}
+ * @api public
+ */
+
+Aggregate.prototype.lookup = function(options) {
+  return this.append({ $lookup: options });
+};
+
+/**
+ * Appends new custom $graphLookup operator(s) to this aggregate pipeline, performing a recursive search on a collection.
+ *
+ * Note that graphLookup can only consume at most 100MB of memory, and does not allow disk use even if `{ allowDiskUse: true }` is specified.
+ *
+ * #### Examples:
+ *      // Suppose we have a collection of courses, where a document might look like `{ _id: 0, name: 'Calculus', prerequisite: 'Trigonometry'}` and `{ _id: 0, name: 'Trigonometry', prerequisite: 'Algebra' }`
+ *      aggregate.graphLookup({ from: 'courses', startWith: '$prerequisite', connectFromField: 'prerequisite', connectToField: 'name', as: 'prerequisites', maxDepth: 3 }) // this will recursively search the 'courses' collection up to 3 prerequisites
+ *
+ * @see $graphLookup https://docs.mongodb.com/manual/reference/operator/aggregation/graphLookup/#pipe._S_graphLookup
+ * @param {Object} options to $graphLookup as described in the above link
+ * @return {Aggregate}
+ * @api public
+ */
+
+Aggregate.prototype.graphLookup = function(options) {
+  const cloneOptions = {};
+  if (options) {
+    if (!utils.isObject(options)) {
+      throw new TypeError('Invalid graphLookup() argument. Must be an object.');
+    }
+
+    utils.mergeClone(cloneOptions, options);
+    const startWith = cloneOptions.startWith;
+
+    if (startWith && typeof startWith === 'string') {
+      cloneOptions.startWith = cloneOptions.startWith.startsWith('$') ?
+        cloneOptions.startWith :
+        '$' + cloneOptions.startWith;
+    }
+
+  }
+  return this.append({ $graphLookup: cloneOptions });
+};
+
+/**
+ * Appends new custom $sample operator(s) to this aggregate pipeline.
+ *
+ * ####Examples:
+ *
+ *     aggregate.sample(3); // Add a pipeline that picks 3 random documents
+ *
+ * @see $sample https://docs.mongodb.org/manual/reference/operator/aggregation/sample/#pipe._S_sample
+ * @param {Number} size number of random documents to pick
+ * @return {Aggregate}
+ * @api public
+ */
+
+Aggregate.prototype.sample = function(size) {
+  return this.append({ $sample: { size: size } });
+};
+
+/**
+ * Appends a new $sort operator to this aggregate pipeline.
+ *
+ * If an object is passed, values allowed are `asc`, `desc`, `ascending`, `descending`, `1`, and `-1`.
+ *
+ * If a string is passed, it must be a space delimited list of path names. The sort order of each path is ascending unless the path name is prefixed with `-` which will be treated as descending.
+ *
+ * ####Examples:
+ *
+ *     // these are equivalent
+ *     aggregate.sort({ field: 'asc', test: -1 });
+ *     aggregate.sort('field -test');
+ *
+ * @see $sort http://docs.mongodb.org/manual/reference/aggregation/sort/
+ * @param {Object|String} arg
+ * @return {Aggregate} this
+ * @api public
+ */
+
+Aggregate.prototype.sort = function(arg) {
+  // TODO refactor to reuse the query builder logic
+
+  const sort = {};
+
+  if (arg.constructor.name === 'Object') {
+    const desc = ['desc', 'descending', -1];
+    Object.keys(arg).forEach(function(field) {
+      // If sorting by text score, skip coercing into 1/-1
+      if (arg[field] instanceof Object && arg[field].$meta) {
+        sort[field] = arg[field];
+        return;
+      }
+      sort[field] = desc.indexOf(arg[field]) === -1 ? 1 : -1;
+    });
+  } else if (arguments.length === 1 && typeof arg === 'string') {
+    arg.split(/\s+/).forEach(function(field) {
+      if (!field) {
+        return;
+      }
+      const ascend = field[0] === '-' ? -1 : 1;
+      if (ascend === -1) {
+        field = field.substring(1);
+      }
+      sort[field] = ascend;
+    });
+  } else {
+    throw new TypeError('Invalid sort() argument. Must be a string or object.');
+  }
+
+  return this.append({ $sort: sort });
+};
+
+/**
+ * Sets the readPreference option for the aggregation query.
+ *
+ * ####Example:
+ *
+ *     Model.aggregate(..).read('primaryPreferred').exec(callback)
+ *
+ * @param {String} pref one of the listed preference options or their aliases
+ * @param {Array} [tags] optional tags for this query
+ * @return {Aggregate} this
+ * @api public
+ * @see mongodb http://docs.mongodb.org/manual/applications/replication/#read-preference
+ * @see driver http://mongodb.github.com/node-mongodb-native/driver-articles/anintroductionto1_1and2_2.html#read-preferences
+ */
+
+Aggregate.prototype.read = function(pref, tags) {
+  if (!this.options) {
+    this.options = {};
+  }
+  read.call(this, pref, tags);
+  return this;
+};
+
+/**
+ * Sets the readConcern level for the aggregation query.
+ *
+ * ####Example:
+ *
+ *     Model.aggregate(..).readConcern('majority').exec(callback)
+ *
+ * @param {String} level one of the listed read concern level or their aliases
+ * @see mongodb https://docs.mongodb.com/manual/reference/read-concern/
+ * @return {Aggregate} this
+ * @api public
+ */
+
+Aggregate.prototype.readConcern = function(level) {
+  if (!this.options) {
+    this.options = {};
+  }
+  readConcern.call(this, level);
+  return this;
+};
+
+/**
+ * Appends a new $redact operator to this aggregate pipeline.
+ *
+ * If 3 arguments are supplied, Mongoose will wrap them with if-then-else of $cond operator respectively
+ * If `thenExpr` or `elseExpr` is string, make sure it starts with $$, like `$$DESCEND`, `$$PRUNE` or `$$KEEP`.
+ *
+ * ####Example:
+ *
+ *     Model.aggregate(...)
+ *      .redact({
+ *        $cond: {
+ *          if: { $eq: [ '$level', 5 ] },
+ *          then: '$$PRUNE',
+ *          else: '$$DESCEND'
+ *        }
+ *      })
+ *      .exec();
+ *
+ *     // $redact often comes with $cond operator, you can also use the following syntax provided by mongoose
+ *     Model.aggregate(...)
+ *      .redact({ $eq: [ '$level', 5 ] }, '$$PRUNE', '$$DESCEND')
+ *      .exec();
+ *
+ * @param {Object} expression redact options or conditional expression
+ * @param {String|Object} [thenExpr] true case for the condition
+ * @param {String|Object} [elseExpr] false case for the condition
+ * @return {Aggregate} this
+ * @see $redact https://docs.mongodb.com/manual/reference/operator/aggregation/redact/
+ * @api public
+ */
+
+Aggregate.prototype.redact = function(expression, thenExpr, elseExpr) {
+  if (arguments.length === 3) {
+    if ((typeof thenExpr === 'string' && !thenExpr.startsWith('$$')) ||
+        (typeof elseExpr === 'string' && !elseExpr.startsWith('$$'))) {
+      throw new Error('If thenExpr or elseExpr is string, it must start with $$. e.g. $$DESCEND, $$PRUNE, $$KEEP');
+    }
+
+    expression = {
+      $cond: {
+        if: expression,
+        then: thenExpr,
+        else: elseExpr
+      }
+    };
+  } else if (arguments.length !== 1) {
+    throw new TypeError('Invalid arguments');
+  }
+
+  return this.append({ $redact: expression });
+};
+
+/**
+ * Execute the aggregation with explain
+ *
+ * ####Example:
+ *
+ *     Model.aggregate(..).explain(callback)
+ *
+ * @param {Function} callback
+ * @return {Promise}
+ */
+
+Aggregate.prototype.explain = function(callback) {
+  const model = this._model;
+
+  return promiseOrCallback(callback, cb => {
+    if (!this._pipeline.length) {
+      const err = new Error('Aggregate has empty pipeline');
+      return cb(err);
+    }
+
+    prepareDiscriminatorPipeline(this);
+
+    model.hooks.execPre('aggregate', this, error => {
+      if (error) {
+        const _opts = { error: error };
+        return model.hooks.execPost('aggregate', this, [null], _opts, error => {
+          cb(error);
+        });
+      }
+
+      this.options.explain = true;
+
+      model.collection.
+        aggregate(this._pipeline, this.options || {}).
+        explain((error, result) => {
+          const _opts = { error: error };
+          return model.hooks.execPost('aggregate', this, [result], _opts, error => {
+            if (error) {
+              return cb(error);
+            }
+            return cb(null, result);
+          });
+        });
+    });
+  }, model.events);
+};
+
+/**
+ * Sets the allowDiskUse option for the aggregation query (ignored for < 2.6.0)
+ *
+ * ####Example:
+ *
+ *     await Model.aggregate([{ $match: { foo: 'bar' } }]).allowDiskUse(true);
+ *
+ * @param {Boolean} value Should tell server it can use hard drive to store data during aggregation.
+ * @param {Array} [tags] optional tags for this query
+ * @see mongodb http://docs.mongodb.org/manual/reference/command/aggregate/
+ */
+
+Aggregate.prototype.allowDiskUse = function(value) {
+  this.options.allowDiskUse = value;
+  return this;
+};
+
+/**
+ * Sets the hint option for the aggregation query (ignored for < 3.6.0)
+ *
+ * ####Example:
+ *
+ *     Model.aggregate(..).hint({ qty: 1, category: 1 }).exec(callback)
+ *
+ * @param {Object|String} value a hint object or the index name
+ * @see mongodb http://docs.mongodb.org/manual/reference/command/aggregate/
+ */
+
+Aggregate.prototype.hint = function(value) {
+  this.options.hint = value;
+  return this;
+};
+
+/**
+ * Sets the session for this aggregation. Useful for [transactions](/docs/transactions.html).
+ *
+ * ####Example:
+ *
+ *     const session = await Model.startSession();
+ *     await Model.aggregate(..).session(session);
+ *
+ * @param {ClientSession} session
+ * @see mongodb http://docs.mongodb.org/manual/reference/command/aggregate/
+ */
+
+Aggregate.prototype.session = function(session) {
+  if (session == null) {
+    delete this.options.session;
+  } else {
+    this.options.session = session;
+  }
+  return this;
+};
+
+/**
+ * Lets you set arbitrary options, for middleware or plugins.
+ *
+ * ####Example:
+ *
+ *     const agg = Model.aggregate(..).option({ allowDiskUse: true }); // Set the `allowDiskUse` option
+ *     agg.options; // `{ allowDiskUse: true }`
+ *
+ * @param {Object} options keys to merge into current options
+ * @param [options.maxTimeMS] number limits the time this aggregation will run, see [MongoDB docs on `maxTimeMS`](https://docs.mongodb.com/manual/reference/operator/meta/maxTimeMS/)
+ * @param [options.allowDiskUse] boolean if true, the MongoDB server will use the hard drive to store data during this aggregation
+ * @param [options.collation] object see [`Aggregate.prototype.collation()`](./docs/api.html#aggregate_Aggregate-collation)
+ * @param [options.session] ClientSession see [`Aggregate.prototype.session()`](./docs/api.html#aggregate_Aggregate-session)
+ * @see mongodb http://docs.mongodb.org/manual/reference/command/aggregate/
+ * @return {Aggregate} this
+ * @api public
+ */
+
+Aggregate.prototype.option = function(value) {
+  for (const key in value) {
+    this.options[key] = value[key];
+  }
+  return this;
+};
+
+/**
+ * Sets the cursor option option for the aggregation query (ignored for < 2.6.0).
+ * Note the different syntax below: .exec() returns a cursor object, and no callback
+ * is necessary.
+ *
+ * ####Example:
+ *
+ *     const cursor = Model.aggregate(..).cursor({ batchSize: 1000 }).exec();
+ *     cursor.eachAsync(function(doc, i) {
+ *       // use doc
+ *     });
+ *
+ * @param {Object} options
+ * @param {Number} options.batchSize set the cursor batch size
+ * @param {Boolean} [options.useMongooseAggCursor] use experimental mongoose-specific aggregation cursor (for `eachAsync()` and other query cursor semantics)
+ * @return {Aggregate} this
+ * @api public
+ * @see mongodb http://mongodb.github.io/node-mongodb-native/2.0/api/AggregationCursor.html
+ */
+
+Aggregate.prototype.cursor = function(options) {
+  if (!this.options) {
+    this.options = {};
+  }
+  this.options.cursor = options || {};
+  return this;
+};
+
+/**
+ * Sets an option on this aggregation. This function will be deprecated in a
+ * future release. Use the [`cursor()`](./api.html#aggregate_Aggregate-cursor),
+ * [`collation()`](./api.html#aggregate_Aggregate-collation), etc. helpers to
+ * set individual options, or access `agg.options` directly.
+ *
+ * Note that MongoDB aggregations [do **not** support the `noCursorTimeout` flag](https://jira.mongodb.org/browse/SERVER-6036),
+ * if you try setting that flag with this function you will get a "unrecognized field 'noCursorTimeout'" error.
+ *
+ * @param {String} flag
+ * @param {Boolean} value
+ * @return {Aggregate} this
+ * @api public
+ * @deprecated Use [`.option()`](api.html#aggregate_Aggregate-option) instead. Note that MongoDB aggregations do **not** support a `noCursorTimeout` option.
+ */
+
+Aggregate.prototype.addCursorFlag = util.deprecate(function(flag, value) {
+  if (!this.options) {
+    this.options = {};
+  }
+  this.options[flag] = value;
+  return this;
+}, 'Mongoose: `Aggregate#addCursorFlag()` is deprecated, use `option()` instead');
+
+/**
+ * Adds a collation
+ *
+ * ####Example:
+ *
+ *     Model.aggregate(..).collation({ locale: 'en_US', strength: 1 }).exec();
+ *
+ * @param {Object} collation options
+ * @return {Aggregate} this
+ * @api public
+ * @see mongodb http://mongodb.github.io/node-mongodb-native/2.2/api/Collection.html#aggregate
+ */
+
+Aggregate.prototype.collation = function(collation) {
+  if (!this.options) {
+    this.options = {};
+  }
+  this.options.collation = collation;
+  return this;
+};
+
+/**
+ * Combines multiple aggregation pipelines.
+ *
+ * ####Example:
+ *
+ *     Model.aggregate(...)
+ *      .facet({
+ *        books: [{ groupBy: '$author' }],
+ *        price: [{ $bucketAuto: { groupBy: '$price', buckets: 2 } }]
+ *      })
+ *      .exec();
+ *
+ *     // Output: { books: [...], price: [{...}, {...}] }
+ *
+ * @param {Object} facet options
+ * @return {Aggregate} this
+ * @see $facet https://docs.mongodb.com/v3.4/reference/operator/aggregation/facet/
+ * @api public
+ */
+
+Aggregate.prototype.facet = function(options) {
+  return this.append({ $facet: options });
+};
+
+/**
+ * Helper for [Atlas Text Search](https://docs.atlas.mongodb.com/reference/atlas-search/tutorial/)'s
+ * `$search` stage.
+ *
+ * ####Example:
+ *
+ *     Model.aggregate().
+ *      search({
+ *        text: {
+ *          query: 'baseball',
+ *          path: 'plot'
+ *        }
+ *      });
+ *
+ *     // Output: [{ plot: '...', title: '...' }]
+ *
+ * @param {Object} $search options
+ * @return {Aggregate} this
+ * @see $search https://docs.atlas.mongodb.com/reference/atlas-search/tutorial/
+ * @api public
+ */
+
+Aggregate.prototype.search = function(options) {
+  return this.append({ $search: options });
+};
+
+/**
+ * Returns the current pipeline
+ *
+ * ####Example:
+ *
+ *     MyModel.aggregate().match({ test: 1 }).pipeline(); // [{ $match: { test: 1 } }]
+ *
+ * @return {Array}
+ * @api public
+ */
+
+
+Aggregate.prototype.pipeline = function() {
+  return this._pipeline;
+};
+
+/**
+ * Executes the aggregate pipeline on the currently bound Model.
+ *
+ * ####Example:
+ *
+ *     aggregate.exec(callback);
+ *
+ *     // Because a promise is returned, the `callback` is optional.
+ *     const promise = aggregate.exec();
+ *     promise.then(..);
+ *
+ * @see Promise #promise_Promise
+ * @param {Function} [callback]
+ * @return {Promise}
+ * @api public
+ */
+
+Aggregate.prototype.exec = function(callback) {
+  if (!this._model) {
+    throw new Error('Aggregate not bound to any Model');
+  }
+  const model = this._model;
+  const collection = this._model.collection;
+
+  applyGlobalMaxTimeMS(this.options, model);
+
+  if (this.options && this.options.cursor) {
+    return new AggregationCursor(this);
+  }
+
+  return promiseOrCallback(callback, cb => {
+    prepareDiscriminatorPipeline(this);
+    stringifyAccumulatorOptions(this._pipeline);
+
+    model.hooks.execPre('aggregate', this, error => {
+      if (error) {
+        const _opts = { error: error };
+        return model.hooks.execPost('aggregate', this, [null], _opts, error => {
+          cb(error);
+        });
+      }
+      if (!this._pipeline.length) {
+        return cb(new Error('Aggregate has empty pipeline'));
+      }
+
+      const options = utils.clone(this.options || {});
+      collection.aggregate(this._pipeline, options, (error, cursor) => {
+        if (error) {
+          const _opts = { error: error };
+          return model.hooks.execPost('aggregate', this, [null], _opts, error => {
+            if (error) {
+              return cb(error);
+            }
+            return cb(null);
+          });
+        }
+        cursor.toArray((error, result) => {
+          const _opts = { error: error };
+          model.hooks.execPost('aggregate', this, [result], _opts, (error, result) => {
+            if (error) {
+              return cb(error);
+            }
+
+            cb(null, result);
+          });
+        });
+      });
+    });
+  }, model.events);
+};
+
+/**
+ * Provides promise for aggregate.
+ *
+ * ####Example:
+ *
+ *     Model.aggregate(..).then(successCallback, errorCallback);
+ *
+ * @see Promise #promise_Promise
+ * @param {Function} [resolve] successCallback
+ * @param {Function} [reject]  errorCallback
+ * @return {Promise}
+ */
+Aggregate.prototype.then = function(resolve, reject) {
+  return this.exec().then(resolve, reject);
+};
+
+/**
+ * Executes the query returning a `Promise` which will be
+ * resolved with either the doc(s) or rejected with the error.
+ * Like [`.then()`](#query_Query-then), but only takes a rejection handler.
+ *
+ * @param {Function} [reject]
+ * @return {Promise}
+ * @api public
+ */
+
+Aggregate.prototype.catch = function(reject) {
+  return this.exec().then(null, reject);
+};
+
+/**
+ * Returns an asyncIterator for use with [`for/await/of` loops](https://thecodebarbarian.com/getting-started-with-async-iterators-in-node-js
+ * You do not need to call this function explicitly, the JavaScript runtime
+ * will call it for you.
+ *
+ * ####Example
+ *
+ *     const agg = Model.aggregate([{ $match: { age: { $gte: 25 } } }]);
+ *     for await (const doc of agg) {
+ *       console.log(doc.name);
+ *     }
+ *
+ * Node.js 10.x supports async iterators natively without any flags. You can
+ * enable async iterators in Node.js 8.x using the [`--harmony_async_iteration` flag](https://github.com/tc39/proposal-async-iteration/issues/117#issuecomment-346695187).
+ *
+ * **Note:** This function is not set if `Symbol.asyncIterator` is undefined. If
+ * `Symbol.asyncIterator` is undefined, that means your Node.js version does not
+ * support async iterators.
+ *
+ * @method Symbol.asyncIterator
+ * @memberOf Aggregate
+ * @instance
+ * @api public
+ */
+
+if (Symbol.asyncIterator != null) {
+  Aggregate.prototype[Symbol.asyncIterator] = function() {
+    return this.cursor({ useMongooseAggCursor: true }).
+      exec().
+      transformNull().
+      _transformForAsyncIterator();
+  };
+}
+
+/*!
+ * Helpers
+ */
+
+/**
+ * Checks whether an object is likely a pipeline operator
+ *
+ * @param {Object} obj object to check
+ * @return {Boolean}
+ * @api private
+ */
+
+function isOperator(obj) {
+  if (typeof obj !== 'object') {
+    return false;
+  }
+
+  const k = Object.keys(obj);
+
+  return k.length === 1 && k.some(key => { return key[0] === '$'; });
+}
+
+/*!
+ * Adds the appropriate `$match` pipeline step to the top of an aggregate's
+ * pipeline, should it's model is a non-root discriminator type. This is
+ * analogous to the `prepareDiscriminatorCriteria` function in `lib/query.js`.
+ *
+ * @param {Aggregate} aggregate Aggregate to prepare
+ */
+
+Aggregate._prepareDiscriminatorPipeline = prepareDiscriminatorPipeline;
+
+function prepareDiscriminatorPipeline(aggregate) {
+  const schema = aggregate._model.schema;
+  const discriminatorMapping = schema && schema.discriminatorMapping;
+
+  if (discriminatorMapping && !discriminatorMapping.isRoot) {
+    const originalPipeline = aggregate._pipeline;
+    const discriminatorKey = discriminatorMapping.key;
+    const discriminatorValue = discriminatorMapping.value;
+
+    // If the first pipeline stage is a match and it doesn't specify a `__t`
+    // key, add the discriminator key to it. This allows for potential
+    // aggregation query optimizations not to be disturbed by this feature.
+    if (originalPipeline[0] && originalPipeline[0].$match && !originalPipeline[0].$match[discriminatorKey]) {
+      originalPipeline[0].$match[discriminatorKey] = discriminatorValue;
+      // `originalPipeline` is a ref, so there's no need for
+      // aggregate._pipeline = originalPipeline
+    } else if (originalPipeline[0] && originalPipeline[0].$geoNear) {
+      originalPipeline[0].$geoNear.query =
+          originalPipeline[0].$geoNear.query || {};
+      originalPipeline[0].$geoNear.query[discriminatorKey] = discriminatorValue;
+    } else if (originalPipeline[0] && originalPipeline[0].$search) {
+      if (originalPipeline[1] && originalPipeline[1].$match != null) {
+        originalPipeline[1].$match[discriminatorKey] = originalPipeline[1].$match[discriminatorKey] || discriminatorValue;
+      } else {
+        const match = {};
+        match[discriminatorKey] = discriminatorValue;
+        originalPipeline.splice(1, 0, { $match: match });
+      }
+    } else {
+      const match = {};
+      match[discriminatorKey] = discriminatorValue;
+      aggregate._pipeline.unshift({ $match: match });
+    }
+  }
+}
+
+/*!
+ * Exports
+ */
+
+module.exports = Aggregate;