1 files changed, 61 insertions, 0 deletions
diff --git a/node_modules/mongodb/lib/read_concern.js b/node_modules/mongodb/lib/read_concern.js
new file mode 100644
index 0000000..b48b8e0
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+++ b/node_modules/mongodb/lib/read_concern.js
@@ -0,0 +1,61 @@
+'use strict';
+
+/**
+ * The **ReadConcern** class is a class that represents a MongoDB ReadConcern.
+ * @class
+ * @property {string} level The read concern level
+ * @see https://docs.mongodb.com/manual/reference/read-concern/index.html
+ */
+class ReadConcern {
+  /**
+   * Constructs a ReadConcern from the read concern properties.
+   * @param {string} [level] The read concern level ({'local'|'available'|'majority'|'linearizable'|'snapshot'})
+   */
+  constructor(level) {
+    if (level != null) {
+      this.level = level;
+    }
+  }
+
+  /**
+   * Construct a ReadConcern given an options object.
+   *
+   * @param {object} options The options object from which to extract the write concern.
+   * @return {ReadConcern}
+   */
+  static fromOptions(options) {
+    if (options == null) {
+      return;
+    }
+
+    if (options.readConcern) {
+      if (options.readConcern instanceof ReadConcern) {
+        return options.readConcern;
+      }
+
+      return new ReadConcern(options.readConcern.level);
+    }
+
+    if (options.level) {
+      return new ReadConcern(options.level);
+    }
+  }
+
+  static get MAJORITY() {
+    return 'majority';
+  }
+
+  static get AVAILABLE() {
+    return 'available';
+  }
+
+  static get LINEARIZABLE() {
+    return 'linearizable';
+  }
+
+  static get SNAPSHOT() {
+    return 'snapshot';
+  }
+}
+
+module.exports = ReadConcern;