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diff --git a/node_modules/mongodb/lib/collection.js b/node_modules/mongodb/lib/collection.js
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+"use strict";
+
+var checkCollectionName = require('./utils').checkCollectionName
+  , ObjectID = require('mongodb-core').BSON.ObjectID
+  , Long = require('mongodb-core').BSON.Long
+  , Code = require('mongodb-core').BSON.Code
+  , f = require('util').format
+  , AggregationCursor = require('./aggregation_cursor')
+  , MongoError = require('mongodb-core').MongoError
+  , shallowClone = require('./utils').shallowClone
+  , isObject = require('./utils').isObject
+  , toError = require('./utils').toError
+  , normalizeHintField = require('./utils').normalizeHintField
+  , handleCallback = require('./utils').handleCallback
+  , decorateCommand = require('./utils').decorateCommand
+  , formattedOrderClause = require('./utils').formattedOrderClause
+  , ReadPreference = require('./read_preference')
+  , CoreReadPreference = require('mongodb-core').ReadPreference
+  , CommandCursor = require('./command_cursor')
+  , Define = require('./metadata')
+  , Cursor = require('./cursor')
+  , unordered = require('./bulk/unordered')
+  , ordered = require('./bulk/ordered');
+
+/**
+ * @fileOverview The **Collection** class is an internal class that embodies a MongoDB collection
+ * allowing for insert/update/remove/find and other command operation on that MongoDB collection.
+ *
+ * **COLLECTION Cannot directly be instantiated**
+ * @example
+ * var MongoClient = require('mongodb').MongoClient,
+ *   test = require('assert');
+ * // Connection url
+ * var url = 'mongodb://localhost:27017/test';
+ * // Connect using MongoClient
+ * MongoClient.connect(url, function(err, db) {
+ *   // Create a collection we want to drop later
+ *   var col = db.collection('createIndexExample1');
+ *   // Show that duplicate records got dropped
+ *   col.find({}).toArray(function(err, items) {
+ *     test.equal(null, err);
+ *     test.equal(4, items.length);
+ *     db.close();
+ *   });
+ * });
+ */
+
+/**
+ * Create a new Collection instance (INTERNAL TYPE, do not instantiate directly)
+ * @class
+ * @property {string} collectionName Get the collection name.
+ * @property {string} namespace Get the full collection namespace.
+ * @property {object} writeConcern The current write concern values.
+ * @property {object} readConcern The current read concern values.
+ * @property {object} hint Get current index hint for collection.
+ * @return {Collection} a Collection instance.
+ */
+var Collection = function(db, topology, dbName, name, pkFactory, options) {
+  checkCollectionName(name);
+  var self = this;
+  // Unpack variables
+  var internalHint = null;
+  var opts = options != null && ('object' === typeof options) ? options : {};
+  var slaveOk = options == null || options.slaveOk == null ? db.slaveOk : options.slaveOk;
+  var serializeFunctions = options == null || options.serializeFunctions == null ? db.serializeFunctions : options.serializeFunctions;
+  var raw = options == null || options.raw == null ? db.raw : options.raw;
+  var readPreference = null;
+  var collectionHint = null;
+  var namespace = f("%s.%s", dbName, name);
+
+  // Get the promiseLibrary
+  var promiseLibrary = options.promiseLibrary;
+
+  // No promise library selected fall back
+  if(!promiseLibrary) {
+    promiseLibrary = typeof global.Promise == 'function' ?
+      global.Promise : require('es6-promise').Promise;
+  }
+
+  // Assign the right collection level readPreference
+  if(options && options.readPreference) {
+    readPreference = options.readPreference;
+  } else if(db.options.readPreference) {
+    readPreference = db.options.readPreference;
+  }
+
+  // Set custom primary key factory if provided
+  pkFactory = pkFactory == null
+    ? ObjectID
+    : pkFactory;
+
+  // Internal state
+  this.s = {
+    // Set custom primary key factory if provided
+      pkFactory: pkFactory
+    // Db
+    , db: db
+    // Topology
+    , topology: topology
+    // dbName
+    , dbName: dbName
+    // Options
+    , options: options
+    // Namespace
+    , namespace: namespace
+    // Read preference
+    , readPreference: readPreference
+    // Raw
+    , raw: raw
+    // SlaveOK
+    , slaveOk: slaveOk
+    // Serialize functions
+    , serializeFunctions: serializeFunctions
+    // internalHint
+    , internalHint: internalHint
+    // collectionHint
+    , collectionHint: collectionHint
+    // Name
+    , name: name
+    // Promise library
+    , promiseLibrary: promiseLibrary
+    // Read Concern
+    , readConcern: options.readConcern
+  }
+}
+
+var define = Collection.define = new Define('Collection', Collection, false);
+
+Object.defineProperty(Collection.prototype, 'collectionName', {
+  enumerable: true, get: function() { return this.s.name; }
+});
+
+Object.defineProperty(Collection.prototype, 'namespace', {
+  enumerable: true, get: function() { return this.s.namespace; }
+});
+
+Object.defineProperty(Collection.prototype, 'readConcern', {
+  enumerable: true, get: function() { return this.s.readConcern || {level: 'local'}; }
+});
+
+Object.defineProperty(Collection.prototype, 'writeConcern', {
+  enumerable:true,
+  get: function() {
+    var ops = {};
+    if(this.s.options.w != null) ops.w = this.s.options.w;
+    if(this.s.options.j != null) ops.j = this.s.options.j;
+    if(this.s.options.fsync != null) ops.fsync = this.s.options.fsync;
+    if(this.s.options.wtimeout != null) ops.wtimeout = this.s.options.wtimeout;
+    return ops;
+  }
+});
+
+/**
+ * @ignore
+ */
+Object.defineProperty(Collection.prototype, "hint", {
+    enumerable: true
+  , get: function () { return this.s.collectionHint; }
+  , set: function (v) { this.s.collectionHint = normalizeHintField(v); }
+});
+
+/**
+ * Creates a cursor for a query that can be used to iterate over results from MongoDB
+ * @method
+ * @param {object} query The cursor query object.
+ * @throws {MongoError}
+ * @return {Cursor}
+ */
+Collection.prototype.find = function() {
+  var options
+    , args = Array.prototype.slice.call(arguments, 0)
+    , has_callback = typeof args[args.length - 1] === 'function'
+    , has_weird_callback = typeof args[0] === 'function'
+    , callback = has_callback ? args.pop() : (has_weird_callback ? args.shift() : null)
+    , len = args.length
+    , selector = len >= 1 ? args[0] : {}
+    , fields = len >= 2 ? args[1] : undefined;
+
+  if(len === 1 && has_weird_callback) {
+    // backwards compat for callback?, options case
+    selector = {};
+    options = args[0];
+  }
+
+  if(len === 2 && fields !== undefined && !Array.isArray(fields)) {
+    var fieldKeys = Object.keys(fields);
+    var is_option = false;
+
+    for(var i = 0; i < fieldKeys.length; i++) {
+      if(testForFields[fieldKeys[i]] != null) {
+        is_option = true;
+        break;
+      }
+    }
+
+    if(is_option) {
+      options = fields;
+      fields = undefined;
+    } else {
+      options = {};
+    }
+  } else if(len === 2 && Array.isArray(fields) && !Array.isArray(fields[0])) {
+    var newFields = {};
+    // Rewrite the array
+    for(var i = 0; i < fields.length; i++) {
+      newFields[fields[i]] = 1;
+    }
+    // Set the fields
+    fields = newFields;
+  }
+
+  if(3 === len) {
+    options = args[2];
+  }
+
+  // Ensure selector is not null
+  selector = selector == null ? {} : selector;
+  // Validate correctness off the selector
+  var object = selector;
+  if(Buffer.isBuffer(object)) {
+    var object_size = object[0] | object[1] << 8 | object[2] << 16 | object[3] << 24;
+    if(object_size != object.length)  {
+      var error = new Error("query selector raw message size does not match message header size [" + object.length + "] != [" + object_size + "]");
+      error.name = 'MongoError';
+      throw error;
+    }
+  }
+
+  // Validate correctness of the field selector
+  var object = fields;
+  if(Buffer.isBuffer(object)) {
+    var object_size = object[0] | object[1] << 8 | object[2] << 16 | object[3] << 24;
+    if(object_size != object.length)  {
+      var error = new Error("query fields raw message size does not match message header size [" + object.length + "] != [" + object_size + "]");
+      error.name = 'MongoError';
+      throw error;
+    }
+  }
+
+  // Check special case where we are using an objectId
+  if(selector instanceof ObjectID || (selector != null && selector._bsontype == 'ObjectID')) {
+    selector = {_id:selector};
+  }
+
+  // If it's a serialized fields field we need to just let it through
+  // user be warned it better be good
+  if(options && options.fields && !(Buffer.isBuffer(options.fields))) {
+    fields = {};
+
+    if(Array.isArray(options.fields)) {
+      if(!options.fields.length) {
+        fields['_id'] = 1;
+      } else {
+        for (var i = 0, l = options.fields.length; i < l; i++) {
+          fields[options.fields[i]] = 1;
+        }
+      }
+    } else {
+      fields = options.fields;
+    }
+  }
+
+  if (!options) options = {};
+
+  var newOptions = {};
+  // Make a shallow copy of options
+  for (var key in options) {
+    newOptions[key] = options[key];
+  }
+
+  // Unpack options
+  newOptions.skip = len > 3 ? args[2] : options.skip ? options.skip : 0;
+  newOptions.limit = len > 3 ? args[3] : options.limit ? options.limit : 0;
+  newOptions.raw = options.raw != null && typeof options.raw === 'boolean' ? options.raw : this.s.raw;
+  newOptions.hint = options.hint != null ? normalizeHintField(options.hint) : this.s.collectionHint;
+  newOptions.timeout = len == 5 ? args[4] : typeof options.timeout === 'undefined' ? undefined : options.timeout;
+  // // If we have overridden slaveOk otherwise use the default db setting
+  newOptions.slaveOk = options.slaveOk != null ? options.slaveOk : this.s.db.slaveOk;
+
+  // Add read preference if needed
+  newOptions = getReadPreference(this, newOptions, this.s.db, this);
+  // Set slave ok to true if read preference different from primary
+  if(newOptions.readPreference != null
+    && (newOptions.readPreference != 'primary' || newOptions.readPreference.mode != 'primary')) {
+    newOptions.slaveOk = true;
+  }
+
+  // Ensure the query is an object
+  if(selector != null && typeof selector != 'object') {
+    throw MongoError.create({message: "query selector must be an object", driver:true });
+  }
+
+  // Build the find command
+  var findCommand = {
+      find: this.s.namespace
+    , limit: newOptions.limit
+    , skip: newOptions.skip
+    , query: selector
+  }
+
+  // Ensure we use the right await data option
+  if(typeof newOptions.awaitdata == 'boolean')  {
+    newOptions.awaitData = newOptions.awaitdata
+  };
+
+  // Translate to new command option noCursorTimeout
+  if(typeof newOptions.timeout == 'boolean') newOptions.noCursorTimeout = newOptions.timeout;
+
+  // Merge in options to command
+  for(var name in newOptions) {
+    if(newOptions[name] != null) findCommand[name] = newOptions[name];
+  }
+
+  // Format the fields
+  var formatFields = function(fields) {
+    var object = {};
+    if(Array.isArray(fields)) {
+      for(var i = 0; i < fields.length; i++) {
+        if(Array.isArray(fields[i])) {
+          object[fields[i][0]] = fields[i][1];
+        } else {
+          object[fields[i][0]] = 1;
+        }
+      }
+    } else {
+      object = fields;
+    }
+
+    return object;
+  }
+
+  // Special treatment for the fields selector
+  if(fields) findCommand.fields = formatFields(fields);
+
+  // Add db object to the new options
+  newOptions.db = this.s.db;
+
+  // Add the promise library
+  newOptions.promiseLibrary = this.s.promiseLibrary;
+
+  // Set raw if available at collection level
+  if(newOptions.raw == null && this.s.raw) newOptions.raw = this.s.raw;
+
+  // Sort options
+  if(findCommand.sort)
+    findCommand.sort = formattedOrderClause(findCommand.sort);
+
+  // Set the readConcern
+  if(this.s.readConcern) {
+    findCommand.readConcern = this.s.readConcern;
+  }
+
+  // Create the cursor
+  if(typeof callback == 'function') return handleCallback(callback, null, this.s.topology.cursor(this.s.namespace, findCommand, newOptions));
+  return this.s.topology.cursor(this.s.namespace, findCommand, newOptions);
+}
+
+define.classMethod('find', {callback: false, promise:false, returns: [Cursor]});
+
+/**
+ * Inserts a single document into MongoDB. If documents passed in do not contain the **_id** field,
+ * one will be added to each of the documents missing it by the driver, mutating the document. This behavior
+ * can be overridden by setting the **forceServerObjectId** flag.
+ *
+ * @method
+ * @param {object} doc Document to insert.
+ * @param {object} [options=null] Optional settings.
+ * @param {(number|string)} [options.w=null] The write concern.
+ * @param {number} [options.wtimeout=null] The write concern timeout.
+ * @param {boolean} [options.j=false] Specify a journal write concern.
+ * @param {boolean} [options.serializeFunctions=false] Serialize functions on any object.
+ * @param {boolean} [options.forceServerObjectId=false] Force server to assign _id values instead of driver.
+ * @param {boolean} [options.bypassDocumentValidation=false] Allow driver to bypass schema validation in MongoDB 3.2 or higher.
+ * @param {Collection~insertOneWriteOpCallback} [callback] The command result callback
+ * @return {Promise} returns Promise if no callback passed
+ */
+Collection.prototype.insertOne = function(doc, options, callback) {
+  var self = this;
+  if(typeof options == 'function') callback = options, options = {};
+  options = options || {};
+  if(Array.isArray(doc) && typeof callback == 'function') {
+    return callback(MongoError.create({message: 'doc parameter must be an object', driver:true }));
+  } else if(Array.isArray(doc)) {
+    return new this.s.promiseLibrary(function(resolve, reject) {
+      reject(MongoError.create({message: 'doc parameter must be an object', driver:true }));
+    });
+  }
+
+  // Add ignoreUndfined
+  if(this.s.options.ignoreUndefined) {
+    options = shallowClone(options);
+    options.ignoreUndefined = this.s.options.ignoreUndefined;
+  }
+
+  // Execute using callback
+  if(typeof callback == 'function') return insertOne(self, doc, options, callback);
+
+  // Return a Promise
+  return new this.s.promiseLibrary(function(resolve, reject) {
+    insertOne(self, doc, options, function(err, r) {
+      if(err) return reject(err);
+      resolve(r);
+    });
+  });
+}
+
+var insertOne = function(self, doc, options, callback) {
+  insertDocuments(self, [doc], options, function(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);
+  });
+}
+
+var mapInserManyResults = function(docs, r) {
+  var ids = r.getInsertedIds();
+  var keys = Object.keys(ids);
+  var finalIds = new Array(keys.length);
+
+  for(var i = 0; i < keys.length; i++) {
+    if(ids[keys[i]]._id) {
+      finalIds[ids[keys[i]].index] = ids[keys[i]]._id;
+    }
+  }
+
+  var finalResult = {
+    result: {ok: 1, n: r.insertedCount},
+    ops: docs,
+    insertedCount: r.insertedCount,
+    insertedIds: finalIds
+  };
+
+  if(r.getLastOp()) {
+    finalResult.result.opTime = r.getLastOp();
+  }
+
+  return finalResult;
+}
+
+define.classMethod('insertOne', {callback: true, promise:true});
+
+/**
+ * Inserts an array of documents into MongoDB. If documents passed in do not contain the **_id** field,
+ * one will be added to each of the documents missing it by the driver, mutating the document. This behavior
+ * can be overridden by setting the **forceServerObjectId** flag.
+ *
+ * @method
+ * @param {object[]} docs Documents to insert.
+ * @param {object} [options=null] Optional settings.
+ * @param {(number|string)} [options.w=null] The write concern.
+ * @param {number} [options.wtimeout=null] The write concern timeout.
+ * @param {boolean} [options.j=false] Specify a journal write concern.
+ * @param {boolean} [options.serializeFunctions=false] Serialize functions on any object.
+ * @param {boolean} [options.forceServerObjectId=false] Force server to assign _id values instead of driver.
+ * @param {boolean} [options.bypassDocumentValidation=false] Allow driver to bypass schema validation in MongoDB 3.2 or higher.
+ * @param {Collection~insertWriteOpCallback} [callback] The command result callback
+ * @return {Promise} returns Promise if no callback passed
+ */
+Collection.prototype.insertMany = function(docs, options, callback) {
+  var self = this;
+  if(typeof options == 'function') callback = options, options = {};
+  options = options || {ordered:true};
+  if(!Array.isArray(docs) && typeof callback == 'function') {
+    return callback(MongoError.create({message: 'docs parameter must be an array of documents', driver:true }));
+  } else if(!Array.isArray(docs)) {
+    return new this.s.promiseLibrary(function(resolve, reject) {
+      reject(MongoError.create({message: 'docs parameter must be an array of documents', driver:true }));
+    });
+  }
+
+  // Get the write concern options
+  if(typeof options.checkKeys != 'boolean') {
+    options.checkKeys = true;
+  }
+
+  // If keep going set unordered
+  options['serializeFunctions'] = options['serializeFunctions'] || self.s.serializeFunctions;
+
+  // Set up the force server object id
+  var forceServerObjectId = typeof options.forceServerObjectId == 'boolean'
+    ? options.forceServerObjectId : self.s.db.options.forceServerObjectId;
+
+  // Do we want to force the server to assign the _id key
+  if(forceServerObjectId !== true) {
+    // Add _id if not specified
+    for(var i = 0; i < docs.length; i++) {
+      if(docs[i]._id == null) docs[i]._id = self.s.pkFactory.createPk();
+    }
+  }
+
+  // Generate the bulk write operations
+  var operations = [{
+    insertMany: docs
+  }];
+
+  // Execute using callback
+  if(typeof callback == 'function') return bulkWrite(self, operations, options, function(err, r) {
+    if(err) return callback(err, r);
+    callback(null, mapInserManyResults(docs, r));
+  });
+
+  // Return a Promise
+  return new this.s.promiseLibrary(function(resolve, reject) {
+    // console.log("########## insertMany 0")
+    bulkWrite(self, operations, options, function(err, r) {
+      // console.log("########## insertMany 1")
+      if(err) return reject(err);
+      resolve(mapInserManyResults(docs, r));
+    });
+  });
+}
+
+define.classMethod('insertMany', {callback: true, promise:true});
+
+/**
+ * @typedef {Object} Collection~BulkWriteOpResult
+ * @property {number} insertedCount Number of documents inserted.
+ * @property {number} matchedCount Number of documents matched for update.
+ * @property {number} modifiedCount Number of documents modified.
+ * @property {number} deletedCount Number of documents deleted.
+ * @property {number} upsertedCount Number of documents upserted.
+ * @property {object} insertedIds Inserted document generated Id's, hash key is the index of the originating operation
+ * @property {object} upsertedIds Upserted document generated Id's, hash key is the index of the originating operation
+ * @property {object} result The command result object.
+ */
+
+/**
+ * The callback format for inserts
+ * @callback Collection~bulkWriteOpCallback
+ * @param {MongoError} error An error instance representing the error during the execution.
+ * @param {Collection~BulkWriteOpResult} result The result object if the command was executed successfully.
+ */
+
+/**
+ * Perform a bulkWrite operation without a fluent API
+ *
+ * Legal operation types are
+ *
+ *  { insertOne: { document: { a: 1 } } }
+ *
+ *  { updateOne: { filter: {a:2}, update: {$set: {a:2}}, upsert:true } }
+ *
+ *  { updateMany: { filter: {a:2}, update: {$set: {a:2}}, upsert:true } }
+ *
+ *  { deleteOne: { filter: {c:1} } }
+ *
+ *  { deleteMany: { filter: {c:1} } }
+ *
+ *  { replaceOne: { filter: {c:3}, replacement: {c:4}, upsert:true}}
+ *
+ * If documents passed in do not contain the **_id** field,
+ * one will be added to each of the documents missing it by the driver, mutating the document. This behavior
+ * can be overridden by setting the **forceServerObjectId** flag.
+ *
+ * @method
+ * @param {object[]} operations Bulk operations to perform.
+ * @param {object} [options=null] Optional settings.
+ * @param {(number|string)} [options.w=null] The write concern.
+ * @param {number} [options.wtimeout=null] The write concern timeout.
+ * @param {boolean} [options.j=false] Specify a journal write concern.
+ * @param {boolean} [options.serializeFunctions=false] Serialize functions on any object.
+ * @param {boolean} [options.ordered=true] Execute write operation in ordered or unordered fashion.
+ * @param {boolean} [options.bypassDocumentValidation=false] Allow driver to bypass schema validation in MongoDB 3.2 or higher.
+ * @param {Collection~bulkWriteOpCallback} [callback] The command result callback
+ * @return {Promise} returns Promise if no callback passed
+ */
+Collection.prototype.bulkWrite = function(operations, options, callback) {
+  var self = this;
+  if(typeof options == 'function') callback = options, options = {};
+  options = options || {ordered:true};
+
+  if(!Array.isArray(operations)) {
+    throw MongoError.create({message: "operations must be an array of documents", driver:true });
+  }
+
+  // Execute using callback
+  if(typeof callback == 'function') return bulkWrite(self, operations, options, callback);
+
+  // Return a Promise
+  return new this.s.promiseLibrary(function(resolve, reject) {
+    bulkWrite(self, operations, options, function(err, r) {
+      if(err && r == null) return reject(err);
+      resolve(r);
+    });
+  });
+}
+
+var bulkWrite = function(self, operations, options, callback) {
+  // Add ignoreUndfined
+  if(self.s.options.ignoreUndefined) {
+    options = shallowClone(options);
+    options.ignoreUndefined = self.s.options.ignoreUndefined;
+  }
+
+  // Create the bulk operation
+  var bulk = options.ordered == true || options.ordered == null ? self.initializeOrderedBulkOp(options) : self.initializeUnorderedBulkOp(options);
+
+  // for each op go through and add to the bulk
+  try {
+    for(var i = 0; i < operations.length; i++) {
+      bulk.raw(operations[i]);
+    }
+  } catch(err) {
+    return callback(err, null);
+  }
+
+  // Final options for write concern
+  var finalOptions = writeConcern(shallowClone(options), self.s.db, self, options);
+  var writeCon = finalOptions.writeConcern ? finalOptions.writeConcern : {};
+
+  // Execute the bulk
+  bulk.execute(writeCon, function(err, r) {
+    // We have connection level error
+    if(!r && err) return callback(err, null);
+    // We have single error
+    if(r && r.hasWriteErrors() && r.getWriteErrorCount() == 1) {
+      return callback(toError(r.getWriteErrorAt(0)), r);
+    }
+
+    // console.log("!!!!!! BULK EXECUTE FINISHED")
+    // console.dir(err)
+    // console.dir(r)
+
+    // if(err) return callback(err);
+    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
+    var inserted = r.getInsertedIds();
+    // Map inserted ids
+    for(var i = 0; i < inserted.length; i++) {
+      r.insertedIds[inserted[i].index] = inserted[i]._id;
+    }
+
+    // Upserted documents
+    var upserted = r.getUpsertedIds();
+    // Map upserted ids
+    for(var i = 0; i < upserted.length; i++) {
+      r.upsertedIds[upserted[i].index] = upserted[i]._id;
+    }
+
+    // Check if we have write errors
+    if(r.hasWriteErrors()) {
+      // Get all the errors
+      var errors = r.getWriteErrors();
+      // Return the MongoError object
+      return callback(toError({
+        message: 'write operation failed', code: errors[0].code, writeErrors: errors
+      }), r);
+    }
+
+    // Check if we have a writeConcern error
+    if(r.getWriteConcernError()) {
+      // Return the MongoError object
+      return callback(toError(r.getWriteConcernError()), r);
+    }
+
+    // Return the results
+    callback(null, r);
+  });
+}
+
+var insertDocuments = function(self, 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];
+
+  // Get the write concern options
+  var finalOptions = writeConcern(shallowClone(options), self.s.db, self, options);
+  if(typeof finalOptions.checkKeys != 'boolean') finalOptions.checkKeys = true;
+
+  // If keep going set unordered
+  if(finalOptions.keepGoing == true) finalOptions.ordered = false;
+  finalOptions['serializeFunctions'] = options['serializeFunctions'] || self.s.serializeFunctions;
+
+  // Set up the force server object id
+  var forceServerObjectId = typeof options.forceServerObjectId == 'boolean'
+    ? options.forceServerObjectId : self.s.db.options.forceServerObjectId;
+
+  // Add _id if not specified
+  if(forceServerObjectId !== true){
+    for(var i = 0; i < docs.length; i++) {
+      if(docs[i]._id == null) docs[i]._id = self.s.pkFactory.createPk();
+    }
+  }
+
+  // File inserts
+  self.s.topology.insert(self.s.namespace, docs, finalOptions, function(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);
+  });
+}
+
+define.classMethod('bulkWrite', {callback: true, promise:true});
+
+/**
+ * @typedef {Object} Collection~WriteOpResult
+ * @property {object[]} ops All the documents inserted using insertOne/insertMany/replaceOne. Documents contain the _id field if forceServerObjectId == false for insertOne/insertMany
+ * @property {object} connection The connection object used for the operation.
+ * @property {object} result The command result object.
+ */
+
+/**
+ * The callback format for inserts
+ * @callback Collection~writeOpCallback
+ * @param {MongoError} error An error instance representing the error during the execution.
+ * @param {Collection~WriteOpResult} result The result object if the command was executed successfully.
+ */
+
+/**
+ * @typedef {Object} Collection~insertWriteOpResult
+ * @property {Number} insertedCount The total amount of documents inserted.
+ * @property {object[]} ops All the documents inserted using insertOne/insertMany/replaceOne. Documents contain the _id field if forceServerObjectId == false for insertOne/insertMany
+ * @property {ObjectId[]} insertedIds All the generated _id's for the inserted documents.
+ * @property {object} connection The connection object used for the operation.
+ * @property {object} result The raw command result object returned from MongoDB (content might vary by server version).
+ * @property {Number} result.ok Is 1 if the command executed correctly.
+ * @property {Number} result.n The total count of documents inserted.
+ */
+
+/**
+ * @typedef {Object} Collection~insertOneWriteOpResult
+ * @property {Number} insertedCount The total amount of documents inserted.
+ * @property {object[]} ops All the documents inserted using insertOne/insertMany/replaceOne. Documents contain the _id field if forceServerObjectId == false for insertOne/insertMany
+ * @property {ObjectId} insertedId The driver generated ObjectId for the insert operation.
+ * @property {object} connection The connection object used for the operation.
+ * @property {object} result The raw command result object returned from MongoDB (content might vary by server version).
+ * @property {Number} result.ok Is 1 if the command executed correctly.
+ * @property {Number} result.n The total count of documents inserted.
+ */
+
+/**
+ * The callback format for inserts
+ * @callback Collection~insertWriteOpCallback
+ * @param {MongoError} error An error instance representing the error during the execution.
+ * @param {Collection~insertWriteOpResult} result The result object if the command was executed successfully.
+ */
+
+/**
+ * The callback format for inserts
+ * @callback Collection~insertOneWriteOpCallback
+ * @param {MongoError} error An error instance representing the error during the execution.
+ * @param {Collection~insertOneWriteOpResult} result The result object if the command was executed successfully.
+ */
+
+/**
+ * Inserts a single document or a an array of documents into MongoDB. If documents passed in do not contain the **_id** field,
+ * one will be added to each of the documents missing it by the driver, mutating the document. This behavior
+ * can be overridden by setting the **forceServerObjectId** flag.
+ *
+ * @method
+ * @param {(object|object[])} docs Documents to insert.
+ * @param {object} [options=null] Optional settings.
+ * @param {(number|string)} [options.w=null] The write concern.
+ * @param {number} [options.wtimeout=null] The write concern timeout.
+ * @param {boolean} [options.j=false] Specify a journal write concern.
+ * @param {boolean} [options.serializeFunctions=false] Serialize functions on any object.
+ * @param {boolean} [options.forceServerObjectId=false] Force server to assign _id values instead of driver.
+ * @param {boolean} [options.bypassDocumentValidation=false] Allow driver to bypass schema validation in MongoDB 3.2 or higher.
+ * @param {Collection~insertWriteOpCallback} [callback] The command result callback
+ * @return {Promise} returns Promise if no callback passed
+ * @deprecated Use insertOne, insertMany or bulkWrite
+ */
+Collection.prototype.insert = function(docs, options, callback) {
+  var self = this;
+  if(typeof options == 'function') callback = options, options = {};
+  options = options || {ordered:false};
+  docs = !Array.isArray(docs) ? [docs] : docs;
+
+  if(options.keepGoing == true) {
+    options.ordered = false;
+  }
+
+  return this.insertMany(docs, options, callback);
+}
+
+define.classMethod('insert', {callback: true, promise:true});
+
+/**
+ * @typedef {Object} Collection~updateWriteOpResult
+ * @property {Object} result The raw result returned from MongoDB, field will vary depending on server version.
+ * @property {Number} result.ok Is 1 if the command executed correctly.
+ * @property {Number} result.n The total count of documents scanned.
+ * @property {Number} result.nModified The total count of documents modified.
+ * @property {Object} connection The connection object used for the operation.
+ * @property {Number} matchedCount The number of documents that matched the filter.
+ * @property {Number} modifiedCount The number of documents that were modified.
+ * @property {Number} upsertedCount The number of documents upserted.
+ * @property {Object} upsertedId The upserted id.
+ * @property {ObjectId} upsertedId._id The upserted _id returned from the server.
+ */
+
+/**
+ * The callback format for inserts
+ * @callback Collection~updateWriteOpCallback
+ * @param {MongoError} error An error instance representing the error during the execution.
+ * @param {Collection~updateWriteOpResult} result The result object if the command was executed successfully.
+ */
+
+/**
+ * Update a single document on MongoDB
+ * @method
+ * @param {object} filter The Filter used to select the document to update
+ * @param {object} update The update operations to be applied to the document
+ * @param {object} [options=null] Optional settings.
+ * @param {boolean} [options.upsert=false] Update operation is an upsert.
+ * @param {(number|string)} [options.w=null] The write concern.
+ * @param {number} [options.wtimeout=null] The write concern timeout.
+ * @param {boolean} [options.j=false] Specify a journal write concern.
+ * @param {boolean} [options.bypassDocumentValidation=false] Allow driver to bypass schema validation in MongoDB 3.2 or higher.
+ * @param {Collection~updateWriteOpCallback} [callback] The command result callback
+ * @return {Promise} returns Promise if no callback passed
+ */
+Collection.prototype.updateOne = function(filter, update, options, callback) {
+  var self = this;
+  if(typeof options == 'function') callback = options, options = {};
+  options = shallowClone(options)
+
+  // Add ignoreUndfined
+  if(this.s.options.ignoreUndefined) {
+    options = shallowClone(options);
+    options.ignoreUndefined = this.s.options.ignoreUndefined;
+  }
+
+  // Execute using callback
+  if(typeof callback == 'function') return updateOne(self, filter, update, options, callback);
+
+  // Return a Promise
+  return new this.s.promiseLibrary(function(resolve, reject) {
+    updateOne(self, filter, update, options, function(err, r) {
+      if(err) return reject(err);
+      resolve(r);
+    });
+  });
+}
+
+var updateOne = function(self, filter, update, options, callback) {
+  // Set single document update
+  options.multi = false;
+  // Execute update
+  updateDocuments(self, filter, update, options, function(err, r) {
+    if(callback == null) return;
+    if(err && callback) return callback(err);
+    if(r == null) return callback(null, {result: {ok:1}});
+    r.matchedCount = r.result.n;
+    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] : null;
+    r.upsertedCount = Array.isArray(r.result.upserted) && r.result.upserted.length ? r.result.upserted.length : 0;
+    if(callback) callback(null, r);
+  });
+}
+
+define.classMethod('updateOne', {callback: true, promise:true});
+
+/**
+ * Replace a document on MongoDB
+ * @method
+ * @param {object} filter The Filter used to select the document to update
+ * @param {object} doc The Document that replaces the matching document
+ * @param {object} [options=null] Optional settings.
+ * @param {boolean} [options.upsert=false] Update operation is an upsert.
+ * @param {(number|string)} [options.w=null] The write concern.
+ * @param {number} [options.wtimeout=null] The write concern timeout.
+ * @param {boolean} [options.j=false] Specify a journal write concern.
+ * @param {boolean} [options.bypassDocumentValidation=false] Allow driver to bypass schema validation in MongoDB 3.2 or higher.
+ * @param {Collection~updateWriteOpCallback} [callback] The command result callback
+ * @return {Promise} returns Promise if no callback passed
+ */
+Collection.prototype.replaceOne = function(filter, update, options, callback) {
+  var self = this;
+  if(typeof options == 'function') callback = options, options = {};
+  options = shallowClone(options)
+
+  // Add ignoreUndfined
+  if(this.s.options.ignoreUndefined) {
+    options = shallowClone(options);
+    options.ignoreUndefined = this.s.options.ignoreUndefined;
+  }
+
+  // Execute using callback
+  if(typeof callback == 'function') return replaceOne(self, filter, update, options, callback);
+
+  // Return a Promise
+  return new this.s.promiseLibrary(function(resolve, reject) {
+    replaceOne(self, filter, update, options, function(err, r) {
+      if(err) return reject(err);
+      resolve(r);
+    });
+  });
+}
+
+var replaceOne = function(self, filter, update, options, callback) {
+  // Set single document update
+  options.multi = false;
+  // Execute update
+  updateDocuments(self, filter, update, options, function(err, r) {
+    if(callback == null) return;
+    if(err && callback) return callback(err);
+    if(r == null) return callback(null, {result: {ok:1}});
+    r.matchedCount = r.result.n;
+    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] : null;
+    r.upsertedCount = Array.isArray(r.result.upserted) && r.result.upserted.length ? r.result.upserted.length : 0;
+    r.ops = [update];
+    if(callback) callback(null, r);
+  });
+}
+
+define.classMethod('replaceOne', {callback: true, promise:true});
+
+/**
+ * Update multiple documents on MongoDB
+ * @method
+ * @param {object} filter The Filter used to select the document to update
+ * @param {object} update The update operations to be applied to the document
+ * @param {object} [options=null] Optional settings.
+ * @param {boolean} [options.upsert=false] Update operation is an upsert.
+ * @param {(number|string)} [options.w=null] The write concern.
+ * @param {number} [options.wtimeout=null] The write concern timeout.
+ * @param {boolean} [options.j=false] Specify a journal write concern.
+ * @param {Collection~updateWriteOpCallback} [callback] The command result callback
+ * @return {Promise} returns Promise if no callback passed
+ */
+Collection.prototype.updateMany = function(filter, update, options, callback) {
+  var self = this;
+  if(typeof options == 'function') callback = options, options = {};
+  options = shallowClone(options)
+
+  // Add ignoreUndfined
+  if(this.s.options.ignoreUndefined) {
+    options = shallowClone(options);
+    options.ignoreUndefined = this.s.options.ignoreUndefined;
+  }
+
+  // Execute using callback
+  if(typeof callback == 'function') return updateMany(self, filter, update, options, callback);
+
+  // Return a Promise
+  return new this.s.promiseLibrary(function(resolve, reject) {
+    updateMany(self, filter, update, options, function(err, r) {
+      if(err) return reject(err);
+      resolve(r);
+    });
+  });
+}
+
+var updateMany = function(self, filter, update, options, callback) {
+  // Set single document update
+  options.multi = true;
+  // Execute update
+  updateDocuments(self, filter, update, options, function(err, r) {
+    if(callback == null) return;
+    if(err && callback) return callback(err);
+    if(r == null) return callback(null, {result: {ok:1}});
+    r.matchedCount = r.result.n;
+    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] : null;
+    r.upsertedCount = Array.isArray(r.result.upserted) && r.result.upserted.length ? r.result.upserted.length : 0;
+    if(callback) callback(null, r);
+  });
+}
+
+define.classMethod('updateMany', {callback: true, promise:true});
+
+var updateDocuments = function(self, 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"));
+
+  // Get the write concern options
+  var finalOptions = writeConcern(shallowClone(options), self.s.db, self, 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'] || self.s.serializeFunctions;
+
+  // Execute the operation
+  var op = {q: selector, u: document};
+  op.upsert = typeof options.upsert == 'boolean' ? options.upsert : false;
+  op.multi = typeof options.multi == 'boolean' ? options.multi : false;
+
+  // Update options
+  self.s.topology.update(self.s.namespace, [op], finalOptions, function(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);
+  });
+}
+
+/**
+ * Updates documents.
+ * @method
+ * @param {object} selector The selector for the update operation.
+ * @param {object} document The update document.
+ * @param {object} [options=null] Optional settings.
+ * @param {(number|string)} [options.w=null] The write concern.
+ * @param {number} [options.wtimeout=null] The write concern timeout.
+ * @param {boolean} [options.j=false] Specify a journal write concern.
+ * @param {boolean} [options.upsert=false] Update operation is an upsert.
+ * @param {boolean} [options.multi=false] Update one/all documents with operation.
+ * @param {boolean} [options.bypassDocumentValidation=false] Allow driver to bypass schema validation in MongoDB 3.2 or higher.
+ * @param {Collection~writeOpCallback} [callback] The command result callback
+ * @throws {MongoError}
+ * @return {Promise} returns Promise if no callback passed
+ * @deprecated use updateOne, updateMany or bulkWrite
+ */
+Collection.prototype.update = function(selector, document, options, callback) {
+  var self = this;
+
+  // Add ignoreUndfined
+  if(this.s.options.ignoreUndefined) {
+    options = shallowClone(options);
+    options.ignoreUndefined = this.s.options.ignoreUndefined;
+  }
+
+  // Execute using callback
+  if(typeof callback == 'function') return updateDocuments(self, selector, document, options, callback);
+
+  // Return a Promise
+  return new this.s.promiseLibrary(function(resolve, reject) {
+    updateDocuments(self, selector, document, options, function(err, r) {
+      if(err) return reject(err);
+      resolve(r);
+    });
+  });
+}
+
+define.classMethod('update', {callback: true, promise:true});
+
+/**
+ * @typedef {Object} Collection~deleteWriteOpResult
+ * @property {Object} result The raw result returned from MongoDB, field will vary depending on server version.
+ * @property {Number} result.ok Is 1 if the command executed correctly.
+ * @property {Number} result.n The total count of documents deleted.
+ * @property {Object} connection The connection object used for the operation.
+ * @property {Number} deletedCount The number of documents deleted.
+ */
+
+/**
+ * The callback format for inserts
+ * @callback Collection~deleteWriteOpCallback
+ * @param {MongoError} error An error instance representing the error during the execution.
+ * @param {Collection~deleteWriteOpResult} result The result object if the command was executed successfully.
+ */
+
+/**
+ * Delete a document on MongoDB
+ * @method
+ * @param {object} filter The Filter used to select the document to remove
+ * @param {object} [options=null] Optional settings.
+ * @param {(number|string)} [options.w=null] The write concern.
+ * @param {number} [options.wtimeout=null] The write concern timeout.
+ * @param {boolean} [options.j=false] Specify a journal write concern.
+ * @param {Collection~deleteWriteOpCallback} [callback] The command result callback
+ * @return {Promise} returns Promise if no callback passed
+ */
+Collection.prototype.deleteOne = function(filter, options, callback) {
+  var self = this;
+  if(typeof options == 'function') callback = options, options = {};
+  var options = shallowClone(options);
+
+  // Add ignoreUndfined
+  if(this.s.options.ignoreUndefined) {
+    options = shallowClone(options);
+    options.ignoreUndefined = this.s.options.ignoreUndefined;
+  }
+
+  // Execute using callback
+  if(typeof callback == 'function') return deleteOne(self, filter, options, callback);
+
+  // Return a Promise
+  return new this.s.promiseLibrary(function(resolve, reject) {
+    deleteOne(self, filter, options, function(err, r) {
+      if(err) return reject(err);
+      resolve(r);
+    });
+  });
+}
+
+var deleteOne = function(self, filter, options, callback) {
+  options.single = true;
+  removeDocuments(self, filter, options, function(err, r) {
+    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);
+  });
+}
+
+define.classMethod('deleteOne', {callback: true, promise:true});
+
+Collection.prototype.removeOne = Collection.prototype.deleteOne;
+
+define.classMethod('removeOne', {callback: true, promise:true});
+
+/**
+ * Delete multiple documents on MongoDB
+ * @method
+ * @param {object} filter The Filter used to select the documents to remove
+ * @param {object} [options=null] Optional settings.
+ * @param {(number|string)} [options.w=null] The write concern.
+ * @param {number} [options.wtimeout=null] The write concern timeout.
+ * @param {boolean} [options.j=false] Specify a journal write concern.
+ * @param {Collection~deleteWriteOpCallback} [callback] The command result callback
+ * @return {Promise} returns Promise if no callback passed
+ */
+Collection.prototype.deleteMany = function(filter, options, callback) {
+  var self = this;
+  if(typeof options == 'function') callback = options, options = {};
+  var options = shallowClone(options);
+
+  // Add ignoreUndfined
+  if(this.s.options.ignoreUndefined) {
+    options = shallowClone(options);
+    options.ignoreUndefined = this.s.options.ignoreUndefined;
+  }
+
+  // Execute using callback
+  if(typeof callback == 'function') return deleteMany(self, filter, options, callback);
+
+  // Return a Promise
+  return new this.s.promiseLibrary(function(resolve, reject) {
+    deleteMany(self, filter, options, function(err, r) {
+      if(err) return reject(err);
+      resolve(r);
+    });
+  });
+}
+
+var deleteMany = function(self, filter, options, callback) {
+  options.single = false;
+  removeDocuments(self, filter, options, function(err, r) {
+    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);
+  });
+}
+
+var removeDocuments = function(self, 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 || {};
+
+  // Get the write concern options
+  var finalOptions = writeConcern(shallowClone(options), self.s.db, self, options);
+
+  // If selector is null set empty
+  if(selector == null) selector = {};
+
+  // Build the op
+  var op = {q: selector, limit: 0};
+  if(options.single) op.limit = 1;
+
+  // Execute the remove
+  self.s.topology.remove(self.s.namespace, [op], finalOptions, function(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);
+  });
+}
+
+define.classMethod('deleteMany', {callback: true, promise:true});
+
+Collection.prototype.removeMany = Collection.prototype.deleteMany;
+
+define.classMethod('removeMany', {callback: true, promise:true});
+
+/**
+ * Remove documents.
+ * @method
+ * @param {object} selector The selector for the update operation.
+ * @param {object} [options=null] Optional settings.
+ * @param {(number|string)} [options.w=null] The write concern.
+ * @param {number} [options.wtimeout=null] The write concern timeout.
+ * @param {boolean} [options.j=false] Specify a journal write concern.
+ * @param {boolean} [options.single=false] Removes the first document found.
+ * @param {Collection~writeOpCallback} [callback] The command result callback
+ * @return {Promise} returns Promise if no callback passed
+ * @deprecated use deleteOne, deleteMany or bulkWrite
+ */
+Collection.prototype.remove = function(selector, options, callback) {
+  var self = this;
+
+  // Add ignoreUndfined
+  if(this.s.options.ignoreUndefined) {
+    options = shallowClone(options);
+    options.ignoreUndefined = this.s.options.ignoreUndefined;
+  }
+
+  // Execute using callback
+  if(typeof callback == 'function') return removeDocuments(self, selector, options, callback);
+
+  // Return a Promise
+  return new this.s.promiseLibrary(function(resolve, reject) {
+    removeDocuments(self, selector, options, function(err, r) {
+      if(err) return reject(err);
+      resolve(r);
+    });
+  });
+}
+
+define.classMethod('remove', {callback: true, promise:true});
+
+/**
+ * Save a document. Simple full document replacement function. Not recommended for efficiency, use atomic
+ * operators and update instead for more efficient operations.
+ * @method
+ * @param {object} doc Document to save
+ * @param {object} [options=null] Optional settings.
+ * @param {(number|string)} [options.w=null] The write concern.
+ * @param {number} [options.wtimeout=null] The write concern timeout.
+ * @param {boolean} [options.j=false] Specify a journal write concern.
+ * @param {Collection~writeOpCallback} [callback] The command result callback
+ * @return {Promise} returns Promise if no callback passed
+ * @deprecated use insertOne, insertMany, updateOne or updateMany
+ */
+Collection.prototype.save = function(doc, options, callback) {
+  var self = this;
+  if(typeof options == 'function') callback = options, options = {};
+  options = options || {};
+
+  // Add ignoreUndfined
+  if(this.s.options.ignoreUndefined) {
+    options = shallowClone(options);
+    options.ignoreUndefined = this.s.options.ignoreUndefined;
+  }
+
+  // Execute using callback
+  if(typeof callback == 'function') return save(self, doc, options, callback);
+
+  // Return a Promise
+  return new this.s.promiseLibrary(function(resolve, reject) {
+    save(self, doc, options, function(err, r) {
+      if(err) return reject(err);
+      resolve(r);
+    });
+  });
+}
+
+var save = function(self, doc, options, callback) {
+  // Get the write concern options
+  var finalOptions = writeConcern(shallowClone(options), self.s.db, self, options);
+  // Establish if we need to perform an insert or update
+  if(doc._id != null) {
+    finalOptions.upsert = true;
+    return updateDocuments(self, {_id: doc._id}, doc, finalOptions, callback);
+  }
+
+  // Insert the document
+  insertDocuments(self, [doc], options, function(err, r) {
+    if(callback == null) return;
+    if(doc == null) return handleCallback(callback, null, null);
+    if(err) return handleCallback(callback, err, null);
+    handleCallback(callback, null, r);
+  });
+}
+
+define.classMethod('save', {callback: true, promise:true});
+
+/**
+ * The callback format for results
+ * @callback Collection~resultCallback
+ * @param {MongoError} error An error instance representing the error during the execution.
+ * @param {object} result The result object if the command was executed successfully.
+ */
+
+/**
+ * Fetches the first document that matches the query
+ * @method
+ * @param {object} query Query for find Operation
+ * @param {object} [options=null] Optional settings.
+ * @param {number} [options.limit=0] Sets the limit of documents returned in the query.
+ * @param {(array|object)} [options.sort=null] Set to sort the documents coming back from the query. Array of indexes, [['a', 1]] etc.
+ * @param {object} [options.fields=null] The fields to return in the query. Object of fields to include or exclude (not both), {'a':1}
+ * @param {number} [options.skip=0] Set to skip N documents ahead in your query (useful for pagination).
+ * @param {Object} [options.hint=null] Tell the query to use specific indexes in the query. Object of indexes to use, {'_id':1}
+ * @param {boolean} [options.explain=false] Explain the query instead of returning the data.
+ * @param {boolean} [options.snapshot=false] Snapshot query.
+ * @param {boolean} [options.timeout=false] Specify if the cursor can timeout.
+ * @param {boolean} [options.tailable=false] Specify if the cursor is tailable.
+ * @param {number} [options.batchSize=0] Set the batchSize for the getMoreCommand when iterating over the query results.
+ * @param {boolean} [options.returnKey=false] Only return the index key.
+ * @param {number} [options.maxScan=null] Limit the number of items to scan.
+ * @param {number} [options.min=null] Set index bounds.
+ * @param {number} [options.max=null] Set index bounds.
+ * @param {boolean} [options.showDiskLoc=false] Show disk location of results.
+ * @param {string} [options.comment=null] You can put a $comment field on a query to make looking in the profiler logs simpler.
+ * @param {boolean} [options.raw=false] Return all BSON documents as Raw Buffer documents.
+ * @param {(ReadPreference|string)} [options.readPreference=null] The preferred read preference (ReadPreference.PRIMARY, ReadPreference.PRIMARY_PREFERRED, ReadPreference.SECONDARY, ReadPreference.SECONDARY_PREFERRED, ReadPreference.NEAREST).
+ * @param {boolean} [options.partial=false] Specify if the cursor should return partial results when querying against a sharded system
+ * @param {number} [options.maxTimeMS=null] Number of miliseconds to wait before aborting the query.
+ * @param {Collection~resultCallback} [callback] The command result callback
+ * @return {Promise} returns Promise if no callback passed
+ * @deprecated use find().limit(1).next(function(err, doc){})
+ */
+Collection.prototype.findOne = function() {
+  var self = this;
+  var args = Array.prototype.slice.call(arguments, 0);
+  var callback = args.pop();
+  if(typeof callback != 'function') args.push(callback);
+
+  // Execute using callback
+  if(typeof callback == 'function') return findOne(self, args, callback);
+
+  // Return a Promise
+  return new this.s.promiseLibrary(function(resolve, reject) {
+    findOne(self, args, function(err, r) {
+      if(err) return reject(err);
+      resolve(r);
+    });
+  });
+}
+
+var findOne = function(self, args, callback) {
+  var cursor = self.find.apply(self, args).limit(-1).batchSize(1);
+  // Return the item
+  cursor.next(function(err, item) {
+    if(err != null) return handleCallback(callback, toError(err), null);
+    handleCallback(callback, null, item);
+  });
+}
+
+define.classMethod('findOne', {callback: true, promise:true});
+
+/**
+ * The callback format for the collection method, must be used if strict is specified
+ * @callback Collection~collectionResultCallback
+ * @param {MongoError} error An error instance representing the error during the execution.
+ * @param {Collection} collection The collection instance.
+ */
+
+/**
+ * Rename the collection.
+ *
+ * @method
+ * @param {string} newName New name of of the collection.
+ * @param {object} [options=null] Optional settings.
+ * @param {boolean} [options.dropTarget=false] Drop the target name collection if it previously exists.
+ * @param {Collection~collectionResultCallback} [callback] The results callback
+ * @return {Promise} returns Promise if no callback passed
+ */
+Collection.prototype.rename = function(newName, opt, callback) {
+  var self = this;
+  if(typeof opt == 'function') callback = opt, opt = {};
+  opt = Object.assign({}, opt, {readPreference: ReadPreference.PRIMARY});
+
+  // Execute using callback
+  if(typeof callback == 'function') return rename(self, newName, opt, callback);
+
+  // Return a Promise
+  return new this.s.promiseLibrary(function(resolve, reject) {
+    rename(self, newName, opt, function(err, r) {
+      if(err) return reject(err);
+      resolve(r);
+    });
+  });
+}
+
+var rename = function(self, newName, opt, callback) {
+  // Check the collection name
+  checkCollectionName(newName);
+  // Build the command
+  var renameCollection = f("%s.%s", self.s.dbName, self.s.name);
+  var toCollection =  f("%s.%s", self.s.dbName, newName);
+  var dropTarget = typeof opt.dropTarget == 'boolean' ? opt.dropTarget : false;
+  var cmd = {'renameCollection':renameCollection, 'to':toCollection, 'dropTarget':dropTarget};
+
+  // Execute against admin
+  self.s.db.admin().command(cmd, opt, function(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(self.s.db, self.s.topology, self.s.dbName, newName, self.s.pkFactory, self.s.options));
+    } catch(err) {
+      return handleCallback(callback, toError(err), null);
+    }
+  });
+}
+
+define.classMethod('rename', {callback: true, promise:true});
+
+/**
+ * Drop the collection from the database, removing it permanently. New accesses will create a new collection.
+ *
+ * @method
+ * @param {object} [options=null] Optional settings.
+ * @param {Collection~resultCallback} [callback] The results callback
+ * @return {Promise} returns Promise if no callback passed
+ */
+Collection.prototype.drop = function(options, callback) {
+  var self = this;
+  if(typeof options == 'function') callback = options, options = {};
+  options = options | {};
+
+  // Execute using callback
+  if(typeof callback == 'function') return self.s.db.dropCollection(self.s.name, callback);
+  // Return a Promise
+  return new this.s.promiseLibrary(function(resolve, reject) {
+    self.s.db.dropCollection(self.s.name, options, function(err, r) {
+      if(err) return reject(err);
+      resolve(r);
+    });
+  });
+}
+
+define.classMethod('drop', {callback: true, promise:true});
+
+/**
+ * Returns the options of the collection.
+ *
+ * @method
+ * @param {Collection~resultCallback} [callback] The results callback
+ * @return {Promise} returns Promise if no callback passed
+ */
+Collection.prototype.options = function(callback) {
+  var self = this;
+
+  // Execute using callback
+  if(typeof callback == 'function') return options(self, callback);
+
+  // Return a Promise
+  return new this.s.promiseLibrary(function(resolve, reject) {
+    options(self, function(err, r) {
+      if(err) return reject(err);
+      resolve(r);
+    });
+  });
+}
+
+var options = function(self, callback) {
+  self.s.db.listCollections({name: self.s.name}).toArray(function(err, collections) {
+    if(err) return handleCallback(callback, err);
+    if(collections.length == 0) {
+      return handleCallback(callback, MongoError.create({message: f("collection %s not found", self.s.namespace), driver:true }));
+    }
+
+    handleCallback(callback, err, collections[0].options || null);
+  });
+}
+
+define.classMethod('options', {callback: true, promise:true});
+
+/**
+ * Returns if the collection is a capped collection
+ *
+ * @method
+ * @param {Collection~resultCallback} [callback] The results callback
+ * @return {Promise} returns Promise if no callback passed
+ */
+Collection.prototype.isCapped = function(callback) {
+  var self = this;
+
+  // Execute using callback
+  if(typeof callback == 'function') return isCapped(self, callback);
+
+  // Return a Promise
+  return new this.s.promiseLibrary(function(resolve, reject) {
+    isCapped(self, function(err, r) {
+      if(err) return reject(err);
+      resolve(r);
+    });
+  });
+}
+
+var isCapped = function(self, callback) {
+  self.options(function(err, document) {
+    if(err) return handleCallback(callback, err);
+    handleCallback(callback, null, document && document.capped);
+  });
+}
+
+define.classMethod('isCapped', {callback: true, promise:true});
+
+/**
+ * Creates an index on the db and collection collection.
+ * @method
+ * @param {(string|object)} fieldOrSpec Defines the index.
+ * @param {object} [options=null] Optional settings.
+ * @param {(number|string)} [options.w=null] The write concern.
+ * @param {number} [options.wtimeout=null] The write concern timeout.
+ * @param {boolean} [options.j=false] Specify a journal write concern.
+ * @param {boolean} [options.unique=false] Creates an unique index.
+ * @param {boolean} [options.sparse=false] Creates a sparse index.
+ * @param {boolean} [options.background=false] Creates the index in the background, yielding whenever possible.
+ * @param {boolean} [options.dropDups=false] A unique index cannot be created on a key that has pre-existing duplicate values. If you would like to create the index anyway, keeping the first document the database indexes and deleting all subsequent documents that have duplicate value
+ * @param {number} [options.min=null] For geospatial indexes set the lower bound for the co-ordinates.
+ * @param {number} [options.max=null] For geospatial indexes set the high bound for the co-ordinates.
+ * @param {number} [options.v=null] Specify the format version of the indexes.
+ * @param {number} [options.expireAfterSeconds=null] Allows you to expire data on indexes applied to a data (MongoDB 2.2 or higher)
+ * @param {number} [options.name=null] Override the autogenerated index name (useful if the resulting name is larger than 128 bytes)
+ * @param {Collection~resultCallback} [callback] The command result callback
+ * @return {Promise} returns Promise if no callback passed
+ */
+Collection.prototype.createIndex = function(fieldOrSpec, options, callback) {
+  var self = this;
+  var args = Array.prototype.slice.call(arguments, 1);
+  callback = args.pop();
+  if(typeof callback != 'function') args.push(callback);
+  options = args.length ? args.shift() || {} : {};
+  options = typeof callback === 'function' ? options : callback;
+  options = options == null ? {} : options;
+
+  // Execute using callback
+  if(typeof callback == 'function') return createIndex(self, fieldOrSpec, options, callback);
+
+  // Return a Promise
+  return new this.s.promiseLibrary(function(resolve, reject) {
+    createIndex(self, fieldOrSpec, options, function(err, r) {
+      if(err) return reject(err);
+      resolve(r);
+    });
+  });
+}
+
+var createIndex = function(self, fieldOrSpec, options, callback) {
+  self.s.db.createIndex(self.s.name, fieldOrSpec, options, callback);
+}
+
+define.classMethod('createIndex', {callback: true, promise:true});
+
+/**
+ * Creates 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 {array} indexSpecs An array of index specifications to be created
+ * @param {Collection~resultCallback} [callback] The command result callback
+ * @return {Promise} returns Promise if no callback passed
+ */
+Collection.prototype.createIndexes = function(indexSpecs, callback) {
+  var self = this;
+
+  // Execute using callback
+  if(typeof callback == 'function') return createIndexes(self, indexSpecs, callback);
+
+  // Return a Promise
+  return new this.s.promiseLibrary(function(resolve, reject) {
+    createIndexes(self, indexSpecs, function(err, r) {
+      if(err) return reject(err);
+      resolve(r);
+    });
+  });
+}
+
+var createIndexes = function(self, indexSpecs, callback) {
+  // Ensure we generate the correct name if the parameter is not set
+  for(var i = 0; i < indexSpecs.length; i++) {
+    if(indexSpecs[i].name == null) {
+      var keys = [];
+
+      for(var name in indexSpecs[i].key) {
+        keys.push(f('%s_%s', name, indexSpecs[i].key[name]));
+      }
+
+      // Set the name
+      indexSpecs[i].name = keys.join('_');
+    }
+  }
+
+  // Execute the index
+  self.s.db.command({
+    createIndexes: self.s.name, indexes: indexSpecs
+  }, { readPreference: ReadPreference.PRIMARY }, callback);
+}
+
+define.classMethod('createIndexes', {callback: true, promise:true});
+
+/**
+ * Drops an index from this collection.
+ * @method
+ * @param {string} indexName Name of the index to drop.
+ * @param {object} [options=null] Optional settings.
+ * @param {(number|string)} [options.w=null] The write concern.
+ * @param {number} [options.wtimeout=null] The write concern timeout.
+ * @param {boolean} [options.j=false] Specify a journal write concern.
+ * @param {Collection~resultCallback} [callback] The command result callback
+ * @return {Promise} returns Promise if no callback passed
+ */
+Collection.prototype.dropIndex = function(indexName, options, callback) {
+  var self = this;
+  var args = Array.prototype.slice.call(arguments, 1);
+  callback = args.pop();
+  if(typeof callback != 'function') args.push(callback);
+  options = args.length ? args.shift() || {} : {};
+  // Run only against primary
+  options.readPreference = ReadPreference.PRIMARY;
+
+  // Execute using callback
+  if(typeof callback == 'function') return dropIndex(self, indexName, options, callback);
+
+  // Return a Promise
+  return new this.s.promiseLibrary(function(resolve, reject) {
+    dropIndex(self, indexName, options, function(err, r) {
+      if(err) return reject(err);
+      resolve(r);
+    });
+  });
+}
+
+var dropIndex = function(self, indexName, options, callback) {
+  // Delete index command
+  var cmd = {'deleteIndexes':self.s.name, 'index':indexName};
+
+  // Execute command
+  self.s.db.command(cmd, options, function(err, result) {
+    if(typeof callback != 'function') return;
+    if(err) return handleCallback(callback, err, null);
+    handleCallback(callback, null, result);
+  });
+}
+
+define.classMethod('dropIndex', {callback: true, promise:true});
+
+/**
+ * Drops all indexes from this collection.
+ * @method
+ * @param {Collection~resultCallback} [callback] The command result callback
+ * @return {Promise} returns Promise if no callback passed
+ */
+Collection.prototype.dropIndexes = function(callback) {
+  var self = this;
+
+  // Execute using callback
+  if(typeof callback == 'function') return dropIndexes(self, callback);
+
+  // Return a Promise
+  return new this.s.promiseLibrary(function(resolve, reject) {
+    dropIndexes(self, function(err, r) {
+      if(err) return reject(err);
+      resolve(r);
+    });
+  });
+}
+
+var dropIndexes = function(self, callback) {
+  self.dropIndex('*', function (err, result) {
+    if(err) return handleCallback(callback, err, false);
+    handleCallback(callback, null, true);
+  });
+}
+
+define.classMethod('dropIndexes', {callback: true, promise:true});
+
+/**
+ * Drops all indexes from this collection.
+ * @method
+ * @deprecated use dropIndexes
+ * @param {Collection~resultCallback} callback The command result callback
+ * @return {Promise} returns Promise if no [callback] passed
+ */
+Collection.prototype.dropAllIndexes = Collection.prototype.dropIndexes;
+
+define.classMethod('dropAllIndexes', {callback: true, promise:true});
+
+/**
+ * Reindex all indexes on the collection
+ * Warning: reIndex is a blocking operation (indexes are rebuilt in the foreground) and will be slow for large collections.
+ * @method
+ * @param {Collection~resultCallback} [callback] The command result callback
+ * @return {Promise} returns Promise if no callback passed
+ */
+Collection.prototype.reIndex = function(options, callback) {
+  var self = this;
+  if(typeof options == 'function') callback = options, options = {};
+  options = options || {};
+
+  // Execute using callback
+  if(typeof callback == 'function') return reIndex(self, options, callback);
+
+  // Return a Promise
+  return new this.s.promiseLibrary(function(resolve, reject) {
+    reIndex(self, options, function(err, r) {
+      if(err) return reject(err);
+      resolve(r);
+    });
+  });
+}
+
+var reIndex = function(self, options, callback) {
+  // Reindex
+  var cmd = {'reIndex':self.s.name};
+
+  // Execute the command
+  self.s.db.command(cmd, options, function(err, result) {
+    if(callback == null) return;
+    if(err) return handleCallback(callback, err, null);
+    handleCallback(callback, null, result.ok ? true : false);
+  });
+}
+
+define.classMethod('reIndex', {callback: true, promise:true});
+
+/**
+ * Get the list of all indexes information for the collection.
+ *
+ * @method
+ * @param {object} [options=null] Optional settings.
+ * @param {number} [options.batchSize=null] The batchSize for the returned command cursor or if pre 2.8 the systems batch collection
+ * @param {(ReadPreference|string)} [options.readPreference=null] The preferred read preference (ReadPreference.PRIMARY, ReadPreference.PRIMARY_PREFERRED, ReadPreference.SECONDARY, ReadPreference.SECONDARY_PREFERRED, ReadPreference.NEAREST).
+ * @return {CommandCursor}
+ */
+Collection.prototype.listIndexes = function(options) {
+  options = options || {};
+  // Clone the options
+  options = shallowClone(options);
+  // Determine the read preference in the options.
+  options = getReadPreference(this, options, this.s.db, this);
+  // Set the CommandCursor constructor
+  options.cursorFactory = CommandCursor;
+  // Set the promiseLibrary
+  options.promiseLibrary = this.s.promiseLibrary;
+
+  if(!this.s.topology.capabilities()) {
+    throw new MongoError('cannot connect to server');
+  }
+
+  // console.log("!!!!!!!!!!!!!! HEY 0")
+  // We have a list collections command
+  if(this.s.topology.capabilities().hasListIndexesCommand) {
+    // console.log("!!!!!!!!!!!!!! HEY 0:1")
+    // Cursor options
+    var cursor = options.batchSize ? {batchSize: options.batchSize} : {}
+    // Build the command
+    var command = { listIndexes: this.s.name, cursor: cursor };
+    // console.log("!!!!!!!!!!!!!! HEY 0:2")
+    // Execute the cursor
+    var cursor = this.s.topology.cursor(f('%s.$cmd', this.s.dbName), command, options);
+    // Do we have a readPreference, apply it
+    if(options.readPreference) cursor.setReadPreference(options.readPreference);
+    // console.log("!!!!!!!!!!!!!! HEY 0:3")
+    // Return the cursor
+    return cursor;
+  }
+
+  // console.log("!!!!!!!!!!!!!! HEY 1")
+  // Get the namespace
+  var ns = f('%s.system.indexes', this.s.dbName);
+  // Get the query
+  var cursor = this.s.topology.cursor(ns, {find: ns, query: {ns: this.s.namespace}}, options);
+  // Do we have a readPreference, apply it
+  if(options.readPreference) cursor.setReadPreference(options.readPreference);
+  // Set the passed in batch size if one was provided
+  if(options.batchSize) cursor = cursor.batchSize(options.batchSize);
+  // Return the cursor
+  return cursor;
+};
+
+define.classMethod('listIndexes', {callback: false, promise:false, returns: [CommandCursor]});
+
+/**
+ * Ensures that an index exists, if it does not it creates it
+ * @method
+ * @deprecated use createIndexes instead
+ * @param {(string|object)} fieldOrSpec Defines the index.
+ * @param {object} [options=null] Optional settings.
+ * @param {(number|string)} [options.w=null] The write concern.
+ * @param {number} [options.wtimeout=null] The write concern timeout.
+ * @param {boolean} [options.j=false] Specify a journal write concern.
+ * @param {boolean} [options.unique=false] Creates an unique index.
+ * @param {boolean} [options.sparse=false] Creates a sparse index.
+ * @param {boolean} [options.background=false] Creates the index in the background, yielding whenever possible.
+ * @param {boolean} [options.dropDups=false] A unique index cannot be created on a key that has pre-existing duplicate values. If you would like to create the index anyway, keeping the first document the database indexes and deleting all subsequent documents that have duplicate value
+ * @param {number} [options.min=null] For geospatial indexes set the lower bound for the co-ordinates.
+ * @param {number} [options.max=null] For geospatial indexes set the high bound for the co-ordinates.
+ * @param {number} [options.v=null] Specify the format version of the indexes.
+ * @param {number} [options.expireAfterSeconds=null] Allows you to expire data on indexes applied to a data (MongoDB 2.2 or higher)
+ * @param {number} [options.name=null] Override the autogenerated index name (useful if the resulting name is larger than 128 bytes)
+ * @param {Collection~resultCallback} [callback] The command result callback
+ * @return {Promise} returns Promise if no callback passed
+ */
+Collection.prototype.ensureIndex = function(fieldOrSpec, options, callback) {
+  var self = this;
+  if(typeof options == 'function') callback = options, options = {};
+  options = options || {};
+
+  // Execute using callback
+  if(typeof callback == 'function') return ensureIndex(self, fieldOrSpec, options, callback);
+
+  // Return a Promise
+  return new this.s.promiseLibrary(function(resolve, reject) {
+    ensureIndex(self, fieldOrSpec, options, function(err, r) {
+      if(err) return reject(err);
+      resolve(r);
+    });
+  });
+}
+
+var ensureIndex = function(self, fieldOrSpec, options, callback) {
+  self.s.db.ensureIndex(self.s.name, fieldOrSpec, options, callback);
+}
+
+define.classMethod('ensureIndex', {callback: true, promise:true});
+
+/**
+ * Checks if one or more indexes exist on the collection, fails on first non-existing index
+ * @method
+ * @param {(string|array)} indexes One or more index names to check.
+ * @param {Collection~resultCallback} [callback] The command result callback
+ * @return {Promise} returns Promise if no callback passed
+ */
+Collection.prototype.indexExists = function(indexes, callback) {
+  var self = this;
+
+  // Execute using callback
+  if(typeof callback == 'function') return indexExists(self, indexes, callback);
+
+  // Return a Promise
+  return new this.s.promiseLibrary(function(resolve, reject) {
+    indexExists(self, indexes, function(err, r) {
+      if(err) return reject(err);
+      resolve(r);
+    });
+  });
+}
+
+var indexExists = function(self, indexes, callback) {
+  self.indexInformation(function(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(var 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);
+  });
+}
+
+define.classMethod('indexExists', {callback: true, promise:true});
+
+/**
+ * Retrieves this collections index info.
+ * @method
+ * @param {object} [options=null] Optional settings.
+ * @param {boolean} [options.full=false] Returns the full raw index information.
+ * @param {Collection~resultCallback} [callback] The command result callback
+ * @return {Promise} returns Promise if no callback passed
+ */
+Collection.prototype.indexInformation = function(options, callback) {
+  var self = this;
+  // Unpack calls
+  var args = Array.prototype.slice.call(arguments, 0);
+  callback = args.pop();
+  if(typeof callback != 'function') args.push(callback);
+  options = args.length ? args.shift() || {} : {};
+
+  // Execute using callback
+  if(typeof callback == 'function') return indexInformation(self, options, callback);
+
+  // Return a Promise
+  return new this.s.promiseLibrary(function(resolve, reject) {
+    indexInformation(self, options, function(err, r) {
+      if(err) return reject(err);
+      resolve(r);
+    });
+  });
+}
+
+var indexInformation = function(self, options, callback) {
+  self.s.db.indexInformation(self.s.name, options, callback);
+}
+
+define.classMethod('indexInformation', {callback: true, promise:true});
+
+/**
+ * The callback format for results
+ * @callback Collection~countCallback
+ * @param {MongoError} error An error instance representing the error during the execution.
+ * @param {number} result The count of documents that matched the query.
+ */
+
+/**
+ * Count number of matching documents in the db to a query.
+ * @method
+ * @param {object} query The query for the count.
+ * @param {object} [options=null] Optional settings.
+ * @param {boolean} [options.limit=null] The limit of documents to count.
+ * @param {boolean} [options.skip=null] The number of documents to skip for the count.
+ * @param {string} [options.hint=null] An index name hint for the query.
+ * @param {(ReadPreference|string)} [options.readPreference=null] The preferred read preference (ReadPreference.PRIMARY, ReadPreference.PRIMARY_PREFERRED, ReadPreference.SECONDARY, ReadPreference.SECONDARY_PREFERRED, ReadPreference.NEAREST).
+ * @param {Collection~countCallback} [callback] The command result callback
+ * @return {Promise} returns Promise if no callback passed
+ */
+Collection.prototype.count = function(query, options, callback) {
+  var self = this;
+  var args = Array.prototype.slice.call(arguments, 0);
+  callback = args.pop();
+  if(typeof callback != 'function') args.push(callback);
+  var queryOption = args.length ? args.shift() || {} : {};
+  var optionsOption = args.length ? args.shift() || {} : {};
+
+  // Execute using callback
+  if(typeof callback == 'function') return count(self, queryOption, optionsOption, callback);
+
+  // Check if query is empty
+  query = query || {};
+  options = options || {};
+
+  // Return a Promise
+  return new this.s.promiseLibrary(function(resolve, reject) {
+    count(self, query, options, function(err, r) {
+      if(err) return reject(err);
+      resolve(r);
+    });
+  });
+};
+
+var count = function(self, query, options, callback) {
+  var skip = options.skip;
+  var limit = options.limit;
+  var hint = options.hint;
+  var maxTimeMS = options.maxTimeMS;
+
+  // Final query
+  var cmd = {
+    'count': self.s.name, 'query': query
+  };
+
+  // Add limit and skip if defined
+  if(typeof skip == 'number') cmd.skip = skip;
+  if(typeof limit == 'number') cmd.limit = limit;
+  if(hint) options.hint = hint;
+
+  options = shallowClone(options);
+  // Ensure we have the right read preference inheritance
+  options = getReadPreference(self, options, self.s.db, self);
+
+  // Do we have a readConcern specified
+  if(self.s.readConcern) {
+    cmd.readConcern = self.s.readConcern;
+  }
+
+  // Execute command
+  self.s.db.command(cmd, options, function(err, result) {
+    if(err) return handleCallback(callback, err);
+    handleCallback(callback, null, result.n);
+  });
+}
+
+define.classMethod('count', {callback: true, promise:true});
+
+/**
+ * The distinct command returns returns a list of distinct values for the given key across a collection.
+ * @method
+ * @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=null] Optional settings.
+ * @param {(ReadPreference|string)} [options.readPreference=null] The preferred read preference (ReadPreference.PRIMARY, ReadPreference.PRIMARY_PREFERRED, ReadPreference.SECONDARY, ReadPreference.SECONDARY_PREFERRED, ReadPreference.NEAREST).
+ * @param {Collection~resultCallback} [callback] The command result callback
+ * @return {Promise} returns Promise if no callback passed
+ */
+Collection.prototype.distinct = function(key, query, options, callback) {
+  var self = this;
+  var args = Array.prototype.slice.call(arguments, 1);
+  callback = args.pop();
+  if(typeof callback != 'function') args.push(callback);
+  var queryOption = args.length ? args.shift() || {} : {};
+  var optionsOption = args.length ? args.shift() || {} : {};
+
+  // Execute using callback
+  if(typeof callback == 'function') return distinct(self, key, queryOption, optionsOption, callback);
+
+  // Ensure the query and options are set
+  query = query || {};
+  options = options || {};
+
+  // Return a Promise
+  return new this.s.promiseLibrary(function(resolve, reject) {
+    distinct(self, key, query, options, function(err, r) {
+      if(err) return reject(err);
+      resolve(r);
+    });
+  });
+};
+
+var distinct = function(self, key, query, options, callback) {
+  // maxTimeMS option
+  var maxTimeMS = options.maxTimeMS;
+
+  // Distinct command
+  var cmd = {
+    'distinct': self.s.name, 'key': key, 'query': query
+  };
+
+  options = shallowClone(options);
+  // Ensure we have the right read preference inheritance
+  options = getReadPreference(self, options, self.s.db, self);
+
+  // Do we have a readConcern specified
+  if(self.s.readConcern) {
+    cmd.readConcern = self.s.readConcern;
+  }
+
+  // Execute the command
+  self.s.db.command(cmd, options, function(err, result) {
+    if(err) return handleCallback(callback, err);
+    handleCallback(callback, null, result.values);
+  });
+}
+
+define.classMethod('distinct', {callback: true, promise:true});
+
+/**
+ * Retrieve all the indexes on the collection.
+ * @method
+ * @param {Collection~resultCallback} [callback] The command result callback
+ * @return {Promise} returns Promise if no callback passed
+ */
+Collection.prototype.indexes = function(callback) {
+  var self = this;
+  // Execute using callback
+  if(typeof callback == 'function') return indexes(self, callback);
+
+  // Return a Promise
+  return new this.s.promiseLibrary(function(resolve, reject) {
+    indexes(self, function(err, r) {
+      if(err) return reject(err);
+      resolve(r);
+    });
+  });
+}
+
+var indexes = function(self, callback) {
+  self.s.db.indexInformation(self.s.name, {full:true}, callback);
+}
+
+define.classMethod('indexes', {callback: true, promise:true});
+
+/**
+ * Get all the collection statistics.
+ *
+ * @method
+ * @param {object} [options=null] Optional settings.
+ * @param {number} [options.scale=null] Divide the returned sizes by scale value.
+ * @param {Collection~resultCallback} [callback] The collection result callback
+ * @return {Promise} returns Promise if no callback passed
+ */
+Collection.prototype.stats = function(options, callback) {
+  var self = this;
+  var args = Array.prototype.slice.call(arguments, 0);
+  callback = args.pop();
+  if(typeof callback != 'function') args.push(callback);
+  // Fetch all commands
+  options = args.length ? args.shift() || {} : {};
+
+  // Execute using callback
+  if(typeof callback == 'function') return stats(self, options, callback);
+
+  // Return a Promise
+  return new this.s.promiseLibrary(function(resolve, reject) {
+    stats(self, options, function(err, r) {
+      if(err) return reject(err);
+      resolve(r);
+    });
+  });
+}
+
+var stats = function(self, options, callback) {
+  // Build command object
+  var commandObject = {
+    collStats:self.s.name
+  }
+
+  // Check if we have the scale value
+  if(options['scale'] != null) commandObject['scale'] = options['scale'];
+
+  options = shallowClone(options);
+  // Ensure we have the right read preference inheritance
+  options = getReadPreference(self, options, self.s.db, self);
+
+  // Execute the command
+  self.s.db.command(commandObject, options, callback);
+}
+
+define.classMethod('stats', {callback: true, promise:true});
+
+/**
+ * @typedef {Object} Collection~findAndModifyWriteOpResult
+ * @property {object} value Document returned from findAndModify command.
+ * @property {object} lastErrorObject The raw lastErrorObject returned from the command.
+ * @property {Number} ok Is 1 if the command executed correctly.
+ */
+
+/**
+ * The callback format for inserts
+ * @callback Collection~findAndModifyCallback
+ * @param {MongoError} error An error instance representing the error during the execution.
+ * @param {Collection~findAndModifyWriteOpResult} result The result object if the command was executed successfully.
+ */
+
+/**
+ * Find a document and delete it in one atomic operation, requires a write lock for the duration of the operation.
+ *
+ * @method
+ * @param {object} filter Document selection filter.
+ * @param {object} [options=null] Optional settings.
+ * @param {object} [options.projection=null] Limits the fields to return for all matching documents.
+ * @param {object} [options.sort=null] Determines which document the operation modifies if the query selects multiple documents.
+ * @param {number} [options.maxTimeMS=null] The maximum amount of time to allow the query to run.
+ * @param {Collection~findAndModifyCallback} [callback] The collection result callback
+ * @return {Promise} returns Promise if no callback passed
+ */
+Collection.prototype.findOneAndDelete = function(filter, options, callback) {
+  var self = this;
+  if(typeof options == 'function') callback = options, options = {};
+  options = options || {};
+
+  // Basic validation
+  if(filter == null || typeof filter != 'object') throw toError('filter parameter must be an object');
+
+  // Execute using callback
+  if(typeof callback == 'function') return findOneAndDelete(self, filter, options, callback);
+
+  // Return a Promise
+  return new this.s.promiseLibrary(function(resolve, reject) {
+    options = options || {};
+
+    findOneAndDelete(self, filter, options, function(err, r) {
+      if(err) return reject(err);
+      resolve(r);
+    });
+  });
+}
+
+var findOneAndDelete = function(self, filter, options, callback) {
+  // Final options
+  var finalOptions = shallowClone(options);
+  finalOptions['fields'] = options.projection;
+  finalOptions['remove'] = true;
+  // Execute find and Modify
+  self.findAndModify(
+      filter
+    , options.sort
+    , null
+    , finalOptions
+    , callback
+  );
+}
+
+define.classMethod('findOneAndDelete', {callback: true, promise:true});
+
+/**
+ * Find a document and replace it in one atomic operation, requires a write lock for the duration of the operation.
+ *
+ * @method
+ * @param {object} filter Document selection filter.
+ * @param {object} replacement Document replacing the matching document.
+ * @param {object} [options=null] Optional settings.
+ * @param {object} [options.projection=null] Limits the fields to return for all matching documents.
+ * @param {object} [options.sort=null] Determines which document the operation modifies if the query selects multiple documents.
+ * @param {number} [options.maxTimeMS=null] The maximum amount of time to allow the query to run.
+ * @param {boolean} [options.upsert=false] Upsert the document if it does not exist.
+ * @param {boolean} [options.returnOriginal=true] When false, returns the updated document rather than the original. The default is true.
+ * @param {Collection~findAndModifyCallback} [callback] The collection result callback
+ * @return {Promise} returns Promise if no callback passed
+ */
+Collection.prototype.findOneAndReplace = function(filter, replacement, options, callback) {
+  var self = this;
+  if(typeof options == 'function') callback = options, options = {};
+  options = options || {};
+
+  // Basic validation
+  if(filter == null || typeof filter != 'object') throw toError('filter parameter must be an object');
+  if(replacement == null || typeof replacement != 'object') throw toError('replacement parameter must be an object');
+
+  // Execute using callback
+  if(typeof callback == 'function') return findOneAndReplace(self, filter, replacement, options, callback);
+
+  // Return a Promise
+  return new this.s.promiseLibrary(function(resolve, reject) {
+    options = options || {};
+
+    findOneAndReplace(self, filter, replacement, options, function(err, r) {
+      if(err) return reject(err);
+      resolve(r);
+    });
+  });
+}
+
+var findOneAndReplace = function(self, filter, replacement, options, callback) {
+  // Final options
+  var finalOptions = shallowClone(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;
+
+  // Execute findAndModify
+  self.findAndModify(
+      filter
+    , options.sort
+    , replacement
+    , finalOptions
+    , callback
+  );
+}
+
+define.classMethod('findOneAndReplace', {callback: true, promise:true});
+
+/**
+ * Find a document and update it in one atomic operation, requires a write lock for the duration of the operation.
+ *
+ * @method
+ * @param {object} filter Document selection filter.
+ * @param {object} update Update operations to be performed on the document
+ * @param {object} [options=null] Optional settings.
+ * @param {object} [options.projection=null] Limits the fields to return for all matching documents.
+ * @param {object} [options.sort=null] Determines which document the operation modifies if the query selects multiple documents.
+ * @param {number} [options.maxTimeMS=null] The maximum amount of time to allow the query to run.
+ * @param {boolean} [options.upsert=false] Upsert the document if it does not exist.
+ * @param {boolean} [options.returnOriginal=true] When false, returns the updated document rather than the original. The default is true.
+ * @param {Collection~findAndModifyCallback} [callback] The collection result callback
+ * @return {Promise} returns Promise if no callback passed
+ */
+Collection.prototype.findOneAndUpdate = function(filter, update, options, callback) {
+  var self = this;
+  if(typeof options == 'function') callback = options, options = {};
+  options = options || {};
+
+  // Basic validation
+  if(filter == null || typeof filter != 'object') throw toError('filter parameter must be an object');
+  if(update == null || typeof update != 'object') throw toError('update parameter must be an object');
+
+  // Execute using callback
+  if(typeof callback == 'function') return findOneAndUpdate(self, filter, update, options, callback);
+
+  // Return a Promise
+  return new this.s.promiseLibrary(function(resolve, reject) {
+    options = options || {};
+
+    findOneAndUpdate(self, filter, update, options, function(err, r) {
+      if(err) return reject(err);
+      resolve(r);
+    });
+  });
+}
+
+var findOneAndUpdate = function(self, filter, update, options, callback) {
+  // Final options
+  var finalOptions = shallowClone(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;
+
+  // Execute findAndModify
+  self.findAndModify(
+      filter
+    , options.sort
+    , update
+    , finalOptions
+    , callback
+  );
+}
+
+define.classMethod('findOneAndUpdate', {callback: true, promise:true});
+
+/**
+ * Find and update a document.
+ * @method
+ * @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=null] Optional settings.
+ * @param {(number|string)} [options.w=null] The write concern.
+ * @param {number} [options.wtimeout=null] The write concern timeout.
+ * @param {boolean} [options.j=false] Specify a journal write concern.
+ * @param {boolean} [options.remove=false] Set to true to remove the object before returning.
+ * @param {boolean} [options.upsert=false] Perform an upsert operation.
+ * @param {boolean} [options.new=false] Set to true if you want to return the modified object rather than the original. Ignored for remove.
+ * @param {object} [options.fields=null] Object containing the field projection for the result returned from the operation.
+ * @param {Collection~findAndModifyCallback} [callback] The command result callback
+ * @return {Promise} returns Promise if no callback passed
+ * @deprecated use findOneAndUpdate, findOneAndReplace or findOneAndDelete instead
+ */
+Collection.prototype.findAndModify = function(query, sort, doc, options, callback) {
+  var self = this;
+  var args = Array.prototype.slice.call(arguments, 1);
+  callback = args.pop();
+  if(typeof callback != 'function') args.push(callback);
+  sort = args.length ? args.shift() || [] : [];
+  doc = args.length ? args.shift() : null;
+  options = args.length ? args.shift() || {} : {};
+
+  // Clone options
+  var options = shallowClone(options);
+  // Force read preference primary
+  options.readPreference = ReadPreference.PRIMARY;
+
+  // Execute using callback
+  if(typeof callback == 'function') return findAndModify(self, query, sort, doc, options, callback);
+
+  // Return a Promise
+  return new this.s.promiseLibrary(function(resolve, reject) {
+    options = options || {};
+
+    findAndModify(self, query, sort, doc, options, function(err, r) {
+      if(err) return reject(err);
+      resolve(r);
+    });
+  });
+}
+
+var findAndModify = function(self, query, sort, doc, options, callback) {
+  // Create findAndModify command object
+  var queryObject = {
+     'findandmodify': self.s.name
+   , '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;
+
+  if(options.fields) {
+    queryObject.fields = options.fields;
+  }
+
+  if(doc && !options.remove) {
+    queryObject.update = doc;
+  }
+
+  // Either use override on the function, or go back to default on either the collection
+  // level or db
+  if(options['serializeFunctions'] != null) {
+    options['serializeFunctions'] = options['serializeFunctions'];
+  } else {
+    options['serializeFunctions'] = self.s.serializeFunctions;
+  }
+
+  // No check on the documents
+  options.checkKeys = false;
+
+  // Get the write concern settings
+  var finalOptions = writeConcern(options, self.s.db, self, options);
+
+  // Decorate the findAndModify command with the write Concern
+  if(finalOptions.writeConcern) {
+    queryObject.writeConcern = finalOptions.writeConcern;
+  }
+
+  // Have we specified bypassDocumentValidation
+  if(typeof finalOptions.bypassDocumentValidation == 'boolean') {
+    queryObject.bypassDocumentValidation = finalOptions.bypassDocumentValidation;
+  }
+
+  // Execute the command
+  self.s.db.command(queryObject
+    , options, function(err, result) {
+      if(err) return handleCallback(callback, err, null);
+      return handleCallback(callback, null, result);
+  });
+}
+
+define.classMethod('findAndModify', {callback: true, promise:true});
+
+/**
+ * Find and remove a document.
+ * @method
+ * @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} [options=null] Optional settings.
+ * @param {(number|string)} [options.w=null] The write concern.
+ * @param {number} [options.wtimeout=null] The write concern timeout.
+ * @param {boolean} [options.j=false] Specify a journal write concern.
+ * @param {Collection~resultCallback} [callback] The command result callback
+ * @return {Promise} returns Promise if no callback passed
+ * @deprecated use findOneAndDelete instead
+ */
+Collection.prototype.findAndRemove = function(query, sort, options, callback) {
+  var self = this;
+  var args = Array.prototype.slice.call(arguments, 1);
+  callback = args.pop();
+  if(typeof callback != 'function') args.push(callback);
+  sort = args.length ? args.shift() || [] : [];
+  options = args.length ? args.shift() || {} : {};
+
+  // Execute using callback
+  if(typeof callback == 'function') return findAndRemove(self, query, sort, options, callback);
+
+  // Return a Promise
+  return new this.s.promiseLibrary(function(resolve, reject) {
+    findAndRemove(self, query, sort, options, function(err, r) {
+      if(err) return reject(err);
+      resolve(r);
+    });
+  });
+}
+
+var findAndRemove = function(self, query, sort, options, callback) {
+  // Add the remove option
+  options['remove'] = true;
+  // Execute the callback
+  self.findAndModify(query, sort, null, options, callback);
+}
+
+define.classMethod('findAndRemove', {callback: true, promise:true});
+
+/**
+ * Execute an aggregation framework pipeline against the collection, needs MongoDB >= 2.2
+ * @method
+ * @param {object} pipeline Array containing all the aggregation framework commands for the execution.
+ * @param {object} [options=null] Optional settings.
+ * @param {(ReadPreference|string)} [options.readPreference=null] The preferred read preference (ReadPreference.PRIMARY, ReadPreference.PRIMARY_PREFERRED, ReadPreference.SECONDARY, ReadPreference.SECONDARY_PREFERRED, ReadPreference.NEAREST).
+ * @param {object} [options.cursor=null] Return the query as cursor, on 2.6 > it returns as a real cursor on pre 2.6 it returns as an emulated cursor.
+ * @param {number} [options.cursor.batchSize=null] The batchSize for the cursor
+ * @param {boolean} [options.explain=false] Explain returns the aggregation execution plan (requires mongodb 2.6 >).
+ * @param {boolean} [options.allowDiskUse=false] allowDiskUse lets the server know if it can use disk to store temporary results for the aggregation (requires mongodb 2.6 >).
+ * @param {number} [options.maxTimeMS=null] maxTimeMS specifies a cumulative time limit in milliseconds for processing operations on the cursor. MongoDB interrupts the operation at the earliest following interrupt point.
+ * @param {boolean} [options.bypassDocumentValidation=false] Allow driver to bypass schema validation in MongoDB 3.2 or higher.
+ * @param {Collection~resultCallback} callback The command result callback
+ * @return {(null|AggregationCursor)}
+ */
+Collection.prototype.aggregate = function(pipeline, options, callback) {
+  var self = this;
+  if(Array.isArray(pipeline)) {
+    // Set up callback if one is provided
+    if(typeof options == 'function') {
+      callback = options;
+      options = {};
+    }
+
+    // If we have no options or callback we are doing
+    // a cursor based aggregation
+    if(options == null && callback == null) {
+      options = {};
+    }
+  } else {
+    // Aggregation pipeline passed as arguments on the method
+    var args = Array.prototype.slice.call(arguments, 0);
+    // Get the callback
+    callback = args.pop();
+    // Get the possible options object
+    var opts = args[args.length - 1];
+    // If it contains any of the admissible options pop it of the args
+    options = opts && (opts.readPreference
+      || opts.explain || opts.cursor || opts.out
+      || opts.maxTimeMS || opts.allowDiskUse) ? args.pop() : {};
+      // Left over arguments is the pipeline
+    pipeline = args;
+  }
+
+  // Ignore readConcern option
+  var ignoreReadConcern = false;
+
+  // If out was specified
+  if(typeof options.out == 'string') {
+    pipeline.push({$out: options.out});
+    ignoreReadConcern = true;
+  } else if(pipeline.length > 0 && pipeline[pipeline.length - 1]['$out']) {
+    ignoreReadConcern = true;
+  }
+
+  // Build the command
+  var command = { aggregate : this.s.name, pipeline : pipeline};
+
+  // If we have bypassDocumentValidation set
+  if(typeof options.bypassDocumentValidation == 'boolean') {
+    command.bypassDocumentValidation = options.bypassDocumentValidation;
+  }
+
+  // Do we have a readConcern specified
+  if(!ignoreReadConcern && this.s.readConcern) {
+    command.readConcern = this.s.readConcern;
+  }
+
+  // If we have allowDiskUse defined
+  if(options.allowDiskUse) command.allowDiskUse = options.allowDiskUse;
+  if(typeof options.maxTimeMS == 'number') command.maxTimeMS = options.maxTimeMS;
+
+  options = shallowClone(options);
+  // Ensure we have the right read preference inheritance
+  options = getReadPreference(this, options, this.s.db, this);
+
+  // If explain has been specified add it
+  if(options.explain) command.explain = options.explain;
+
+  // Validate that cursor options is valid
+  if(options.cursor != null && typeof options.cursor != 'object') {
+    throw toError('cursor options must be an object');
+  }
+
+  // promiseLibrary
+  options.promiseLibrary = this.s.promiseLibrary;
+
+  // Set the AggregationCursor constructor
+  options.cursorFactory = AggregationCursor;
+  if(typeof callback != 'function') {
+    if(!this.s.topology.capabilities()) {
+      throw new MongoError('cannot connect to server');
+    }
+
+    if(this.s.topology.capabilities().hasAggregationCursor) {
+      options.cursor = options.cursor || { batchSize : 1000 };
+      command.cursor = options.cursor;
+    }
+
+    // Allow disk usage command
+    if(typeof options.allowDiskUse == 'boolean') command.allowDiskUse = options.allowDiskUse;
+    if(typeof options.maxTimeMS == 'number') command.maxTimeMS = options.maxTimeMS;
+
+    // Execute the cursor
+    return this.s.topology.cursor(this.s.namespace, command, options);
+  }
+
+  var cursor = null;
+  // We do not allow cursor
+  if(options.cursor) {
+    return this.s.topology.cursor(this.s.namespace, command, options);
+  }
+
+  // Execute the command
+  this.s.db.command(command, options, function(err, result) {
+    if(err) {
+      handleCallback(callback, err);
+    } else if(result['err'] || result['errmsg']) {
+      handleCallback(callback, toError(result));
+    } else if(typeof result == 'object' && result['serverPipeline']) {
+      handleCallback(callback, null, result['serverPipeline']);
+    } else if(typeof result == 'object' && result['stages']) {
+      handleCallback(callback, null, result['stages']);
+    } else {
+      handleCallback(callback, null, result.result);
+    }
+  });
+}
+
+define.classMethod('aggregate', {callback: true, promise:false});
+
+/**
+ * The callback format for results
+ * @callback Collection~parallelCollectionScanCallback
+ * @param {MongoError} error An error instance representing the error during the execution.
+ * @param {Cursor[]} cursors A list of cursors returned allowing for parallel reading of collection.
+ */
+
+/**
+ * Return N number of parallel cursors for a collection allowing parallel reading of entire collection. There are
+ * no ordering guarantees for returned results.
+ * @method
+ * @param {object} [options=null] Optional settings.
+ * @param {(ReadPreference|string)} [options.readPreference=null] The preferred read preference (ReadPreference.PRIMARY, ReadPreference.PRIMARY_PREFERRED, ReadPreference.SECONDARY, ReadPreference.SECONDARY_PREFERRED, ReadPreference.NEAREST).
+ * @param {number} [options.batchSize=null] Set the batchSize for the getMoreCommand when iterating over the query results.
+ * @param {number} [options.numCursors=1] The maximum number of parallel command cursors to return (the number of returned cursors will be in the range 1:numCursors)
+ * @param {boolean} [options.raw=false] Return all BSON documents as Raw Buffer documents.
+ * @param {Collection~parallelCollectionScanCallback} [callback] The command result callback
+ * @return {Promise} returns Promise if no callback passed
+ */
+Collection.prototype.parallelCollectionScan = function(options, callback) {
+  var self = this;
+  if(typeof options == 'function') callback = options, options = {numCursors: 1};
+  // Set number of cursors to 1
+  options.numCursors = options.numCursors || 1;
+  options.batchSize = options.batchSize || 1000;
+
+  options = shallowClone(options);
+  // Ensure we have the right read preference inheritance
+  options = getReadPreference(this, options, this.s.db, this);
+
+  // Add a promiseLibrary
+  options.promiseLibrary = this.s.promiseLibrary;
+
+  // Execute using callback
+  if(typeof callback == 'function') return parallelCollectionScan(self, options, callback);
+
+  // Return a Promise
+  return new this.s.promiseLibrary(function(resolve, reject) {
+    parallelCollectionScan(self, options, function(err, r) {
+      if(err) return reject(err);
+      resolve(r);
+    });
+  });
+}
+
+var parallelCollectionScan = function(self, options, callback) {
+  // Create command object
+  var commandObject = {
+      parallelCollectionScan: self.s.name
+    , numCursors: options.numCursors
+  }
+
+  // Do we have a readConcern specified
+  if(self.s.readConcern) {
+    commandObject.readConcern = self.s.readConcern;
+  }
+
+  // Store the raw value
+  var raw = options.raw;
+  delete options['raw'];
+
+  // Execute the command
+  self.s.db.command(commandObject, options, function(err, result) {
+    if(err) return handleCallback(callback, err, null);
+    if(result == null) return handleCallback(callback, new Error("no result returned for parallelCollectionScan"), null);
+
+    var cursors = [];
+    // Add the raw back to the option
+    if(raw) options.raw = raw;
+    // Create command cursors for each item
+    for(var i = 0; i < result.cursors.length; i++) {
+      var rawId = result.cursors[i].cursor.id
+      // Convert cursorId to Long if needed
+      var cursorId = typeof rawId == 'number' ? Long.fromNumber(rawId) : rawId;
+
+      // Command cursor options
+      var cmd = {
+          batchSize: options.batchSize
+        , cursorId: cursorId
+        , items: result.cursors[i].cursor.firstBatch
+      }
+
+      // Add a command cursor
+      cursors.push(self.s.topology.cursor(self.s.namespace, cursorId, options));
+    }
+
+    handleCallback(callback, null, cursors);
+  });
+}
+
+define.classMethod('parallelCollectionScan', {callback: true, promise:true});
+
+/**
+ * Execute the geoNear command to search for items in the collection
+ *
+ * @method
+ * @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=null] Optional settings.
+ * @param {(ReadPreference|string)} [options.readPreference=null] The preferred read preference (ReadPreference.PRIMARY, ReadPreference.PRIMARY_PREFERRED, ReadPreference.SECONDARY, ReadPreference.SECONDARY_PREFERRED, ReadPreference.NEAREST).
+ * @param {number} [options.num=null] Max number of results to return.
+ * @param {number} [options.minDistance=null] Include results starting at minDistance from a point (2.6 or higher)
+ * @param {number} [options.maxDistance=null] Include results up to maxDistance from the point.
+ * @param {number} [options.distanceMultiplier=null] Include a value to multiply the distances with allowing for range conversions.
+ * @param {object} [options.query=null] Filter the results by a query.
+ * @param {boolean} [options.spherical=false] Perform query using a spherical model.
+ * @param {boolean} [options.uniqueDocs=false] The closest location in a document to the center of the search region will always be returned MongoDB > 2.X.
+ * @param {boolean} [options.includeLocs=false] Include the location data fields in the top level of the results MongoDB > 2.X.
+ * @param {Collection~resultCallback} [callback] The command result callback
+ * @return {Promise} returns Promise if no callback passed
+ */
+Collection.prototype.geoNear = function(x, y, options, callback) {
+  var self = this;
+  var point = typeof(x) == 'object' && x
+    , args = Array.prototype.slice.call(arguments, point?1:2);
+
+  callback = args.pop();
+  if(typeof callback != 'function') args.push(callback);
+  // Fetch all commands
+  options = args.length ? args.shift() || {} : {};
+
+  // Execute using callback
+  if(typeof callback == 'function') return geoNear(self, x, y, point, options, callback);
+
+  // Return a Promise
+  return new this.s.promiseLibrary(function(resolve, reject) {
+    geoNear(self, x, y, point, options, function(err, r) {
+      if(err) return reject(err);
+      resolve(r);
+    });
+  });
+}
+
+var geoNear = function(self, x, y, point, options, callback) {
+  // Build command object
+  var commandObject = {
+    geoNear:self.s.name,
+    near: point || [x, y]
+  }
+
+  options = shallowClone(options);
+  // Ensure we have the right read preference inheritance
+  options = getReadPreference(self, options, self.s.db, self);
+
+  // Exclude readPreference and existing options to prevent user from
+  // shooting themselves in the foot
+  var exclude = {
+    readPreference: true,
+    geoNear: true,
+    near: true
+  };
+
+  // Filter out any excluded objects
+  commandObject = decorateCommand(commandObject, options, exclude);
+
+  // Do we have a readConcern specified
+  if(self.s.readConcern) {
+    commandObject.readConcern = self.s.readConcern;
+  }
+
+  // Execute the command
+  self.s.db.command(commandObject, options, function (err, res) {
+    if(err) return handleCallback(callback, err);
+    if(res.err || res.errmsg) return 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);
+  });
+}
+
+define.classMethod('geoNear', {callback: true, promise:true});
+
+/**
+ * Execute a geo search using a geo haystack index on a collection.
+ *
+ * @method
+ * @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=null] Optional settings.
+ * @param {(ReadPreference|string)} [options.readPreference=null] The preferred read preference (ReadPreference.PRIMARY, ReadPreference.PRIMARY_PREFERRED, ReadPreference.SECONDARY, ReadPreference.SECONDARY_PREFERRED, ReadPreference.NEAREST).
+ * @param {number} [options.maxDistance=null] Include results up to maxDistance from the point.
+ * @param {object} [options.search=null] Filter the results by a query.
+ * @param {number} [options.limit=false] Max number of results to return.
+ * @param {Collection~resultCallback} [callback] The command result callback
+ * @return {Promise} returns Promise if no callback passed
+ */
+Collection.prototype.geoHaystackSearch = function(x, y, options, callback) {
+  var self = this;
+  var args = Array.prototype.slice.call(arguments, 2);
+  callback = args.pop();
+  if(typeof callback != 'function') args.push(callback);
+  // Fetch all commands
+  options = args.length ? args.shift() || {} : {};
+
+  // Execute using callback
+  if(typeof callback == 'function') return geoHaystackSearch(self, x, y, options, callback);
+
+  // Return a Promise
+  return new this.s.promiseLibrary(function(resolve, reject) {
+    geoHaystackSearch(self, x, y, options, function(err, r) {
+      if(err) return reject(err);
+      resolve(r);
+    });
+  });
+}
+
+var geoHaystackSearch = function(self, x, y, options, callback) {
+  // Build command object
+  var commandObject = {
+    geoSearch: self.s.name,
+    near: [x, y]
+  }
+
+  // Remove read preference from hash if it exists
+  commandObject = decorateCommand(commandObject, options, {readPreference: true});
+
+  options = shallowClone(options);
+  // Ensure we have the right read preference inheritance
+  options = getReadPreference(self, options, self.s.db, self);
+
+  // Do we have a readConcern specified
+  if(self.s.readConcern) {
+    commandObject.readConcern = self.s.readConcern;
+  }
+
+  // Execute the command
+  self.s.db.command(commandObject, options, function (err, res) {
+    if(err) return handleCallback(callback, err);
+    if(res.err || res.errmsg) handleCallback(callback, utils.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);
+  });
+}
+
+define.classMethod('geoHaystackSearch', {callback: true, promise:true});
+
+/**
+ * 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();
+var 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}';
+
+/**
+ * Run a group command across a collection
+ *
+ * @method
+ * @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=null] Optional settings.
+ * @param {(ReadPreference|string)} [options.readPreference=null] The preferred read preference (ReadPreference.PRIMARY, ReadPreference.PRIMARY_PREFERRED, ReadPreference.SECONDARY, ReadPreference.SECONDARY_PREFERRED, ReadPreference.NEAREST).
+ * @param {Collection~resultCallback} [callback] The command result callback
+ * @return {Promise} returns Promise if no callback passed
+ */
+Collection.prototype.group = function(keys, condition, initial, reduce, finalize, command, options, callback) {
+  var self = this;
+  var args = Array.prototype.slice.call(arguments, 3);
+  callback = args.pop();
+  if(typeof callback != 'function') args.push(callback);
+  // Fetch all commands
+  reduce = args.length ? args.shift() : null;
+  finalize = args.length ? args.shift() : null;
+  command = args.length ? args.shift() : null;
+  options = args.length ? args.shift() || {} : {};
+
+  // Make sure we are backward compatible
+  if(!(typeof finalize == 'function')) {
+    command = finalize;
+    finalize = null;
+  }
+
+  if (!Array.isArray(keys) && keys instanceof Object && typeof(keys) !== 'function' && !(keys instanceof Code)) {
+    keys = Object.keys(keys);
+  }
+
+  if(typeof reduce === 'function') {
+    reduce = reduce.toString();
+  }
+
+  if(typeof finalize === 'function') {
+    finalize = finalize.toString();
+  }
+
+  // Set up the command as default
+  command = command == null ? true : command;
+
+  // Execute using callback
+  if(typeof callback == 'function') return group(self, keys, condition, initial, reduce, finalize, command, options, callback);
+  // Return a Promise
+  return new this.s.promiseLibrary(function(resolve, reject) {
+    group(self, keys, condition, initial, reduce, finalize, command, options, function(err, r) {
+      if(err) return reject(err);
+      resolve(r);
+    });
+  });
+}
+
+var group = function(self, keys, condition, initial, reduce, finalize, command, options, callback) {
+  // Execute using the command
+  if(command) {
+    var reduceFunction = reduce instanceof Code
+        ? reduce
+        : new Code(reduce);
+
+    var selector = {
+      group: {
+          'ns': self.s.name
+        , '$reduce': reduceFunction
+        , 'cond': condition
+        , 'initial': initial
+        , 'out': "inline"
+      }
+    };
+
+    // if finalize is defined
+    if(finalize != null) selector.group['finalize'] = finalize;
+    // Set up group selector
+    if ('function' === typeof keys || keys instanceof Code) {
+      selector.group.$keyf = keys instanceof Code
+        ? keys
+        : new Code(keys);
+    } else {
+      var hash = {};
+      keys.forEach(function (key) {
+        hash[key] = 1;
+      });
+      selector.group.key = hash;
+    }
+
+    options = shallowClone(options);
+    // Ensure we have the right read preference inheritance
+    options = getReadPreference(self, options, self.s.db, self);
+
+    // Do we have a readConcern specified
+    if(self.s.readConcern) {
+      selector.readConcern = self.s.readConcern;
+    }
+
+    // Execute command
+    self.s.db.command(selector, options, function(err, result) {
+      if(err) return handleCallback(callback, err, null);
+      handleCallback(callback, null, result.retval);
+    });
+  } else {
+    // Create execution scope
+    var scope = reduce != null && reduce instanceof Code
+      ? reduce.scope
+      : {};
+
+    scope.ns = self.s.name;
+    scope.keys = keys;
+    scope.condition = condition;
+    scope.initial = initial;
+
+    // Pass in the function text to execute within mongodb.
+    var groupfn = groupFunction.replace(/ reduce;/, reduce.toString() + ';');
+
+    self.s.db.eval(new Code(groupfn, scope), function (err, results) {
+      if (err) return handleCallback(callback, err, null);
+      handleCallback(callback, null, results.result || results);
+    });
+  }
+}
+
+define.classMethod('group', {callback: true, promise:true});
+
+/**
+ * Functions that are passed as scope args must
+ * be converted to Code instances.
+ * @ignore
+ */
+function processScope (scope) {
+  if(!isObject(scope)) {
+    return scope;
+  }
+
+  var keys = Object.keys(scope);
+  var i = keys.length;
+  var key;
+  var new_scope = {};
+
+  while (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;
+}
+
+/**
+ * Run Map Reduce across a collection. Be aware that the inline option for out will return an array of results not a collection.
+ *
+ * @method
+ * @param {(function|string)} map The mapping function.
+ * @param {(function|string)} reduce The reduce function.
+ * @param {object} [options=null] Optional settings.
+ * @param {(ReadPreference|string)} [options.readPreference=null] The preferred read preference (ReadPreference.PRIMARY, ReadPreference.PRIMARY_PREFERRED, ReadPreference.SECONDARY, ReadPreference.SECONDARY_PREFERRED, ReadPreference.NEAREST).
+ * @param {object} [options.out=null] Sets the output target for the map reduce job. *{inline:1} | {replace:'collectionName'} | {merge:'collectionName'} | {reduce:'collectionName'}*
+ * @param {object} [options.query=null] Query filter object.
+ * @param {object} [options.sort=null] Sorts the input objects using this key. Useful for optimization, like sorting by the emit key for fewer reduces.
+ * @param {number} [options.limit=null] Number of objects to return from collection.
+ * @param {boolean} [options.keeptemp=false] Keep temporary data.
+ * @param {(function|string)} [options.finalize=null] Finalize function.
+ * @param {object} [options.scope=null] Can pass in variables that can be access from map/reduce/finalize.
+ * @param {boolean} [options.jsMode=false] It is possible to make the execution stay in JS. Provided in MongoDB > 2.0.X.
+ * @param {boolean} [options.verbose=false] Provide statistics on job execution time.
+ * @param {boolean} [options.bypassDocumentValidation=false] Allow driver to bypass schema validation in MongoDB 3.2 or higher.
+ * @param {Collection~resultCallback} [callback] The command result callback
+ * @throws {MongoError}
+ * @return {Promise} returns Promise if no callback passed
+ */
+Collection.prototype.mapReduce = function(map, reduce, options, callback) {
+  var self = this;
+  if('function' === typeof options) callback = options, options = {};
+  // Out must allways be defined (make sure we don't break weirdly on pre 1.8+ servers)
+  if(null == options.out) {
+    throw new Error("the out option parameter must be defined, see mongodb docs for possible values");
+  }
+
+  if('function' === typeof map) {
+    map = map.toString();
+  }
+
+  if('function' === typeof reduce) {
+    reduce = reduce.toString();
+  }
+
+  if('function' === typeof options.finalize) {
+    options.finalize = options.finalize.toString();
+  }
+
+  // Execute using callback
+  if(typeof callback == 'function') return mapReduce(self, map, reduce, options, callback);
+
+  // Return a Promise
+  return new this.s.promiseLibrary(function(resolve, reject) {
+    mapReduce(self, map, reduce, options, function(err, r, r1) {
+      if(err) return reject(err);
+      if(!r1) return resolve(r);
+      resolve({results: r, stats: r1});
+    });
+  });
+}
+
+var mapReduce = function(self, map, reduce, options, callback) {
+  var mapCommandHash = {
+      mapreduce: self.s.name
+    , map: map
+    , reduce: reduce
+  };
+
+  // Add any other options passed in
+  for(var n in options) {
+    if('scope' == n) {
+      mapCommandHash[n] = processScope(options[n]);
+    } else {
+      mapCommandHash[n] = options[n];
+    }
+  }
+
+  options = shallowClone(options);
+  // Ensure we have the right read preference inheritance
+  options = getReadPreference(self, options, self.s.db, self);
+
+  // 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')) {
+      options.readPreference = 'primary';
+  } else if(self.s.readConcern) {
+    mapCommandHash.readConcern = self.s.readConcern;
+  }
+
+  // Is bypassDocumentValidation specified
+  if(typeof options.bypassDocumentValidation == 'boolean') {
+    mapCommandHash.bypassDocumentValidation = options.bypassDocumentValidation;
+  }
+
+  // Execute command
+  self.s.db.command(mapCommandHash, {readPreference:options.readPreference}, function (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
+    var 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, result.results, stats);
+    }
+
+    // The returned collection
+    var collection = null;
+
+    // If we have an object it's a different db
+    if(result.result != null && typeof result.result == 'object') {
+      var doc = result.result;
+      collection = self.s.db.db(doc.db).collection(doc.collection);
+    } else {
+      // Create a collection object that wraps the result collection
+      collection = self.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, stats);
+  });
+}
+
+define.classMethod('mapReduce', {callback: true, promise:true});
+
+/**
+ * Initiate a Out of order batch write operation. All operations will be buffered into insert/update/remove commands executed out of order.
+ *
+ * @method
+ * @param {object} [options=null] Optional settings.
+ * @param {(number|string)} [options.w=null] The write concern.
+ * @param {number} [options.wtimeout=null] The write concern timeout.
+ * @param {boolean} [options.j=false] Specify a journal write concern.
+ * @return {UnorderedBulkOperation}
+ */
+Collection.prototype.initializeUnorderedBulkOp = function(options) {
+  options = options || {};
+  options.promiseLibrary = this.s.promiseLibrary;
+  return unordered(this.s.topology, this, options);
+}
+
+define.classMethod('initializeUnorderedBulkOp', {callback: false, promise:false, returns: [ordered.UnorderedBulkOperation]});
+
+/**
+ * Initiate an In order bulk write operation, operations will be serially executed in the order they are added, creating a new operation for each switch in types.
+ *
+ * @method
+ * @param {object} [options=null] Optional settings.
+ * @param {(number|string)} [options.w=null] The write concern.
+ * @param {number} [options.wtimeout=null] The write concern timeout.
+ * @param {boolean} [options.j=false] Specify a journal write concern.
+ * @param {OrderedBulkOperation} callback The command result callback
+ * @return {null}
+ */
+Collection.prototype.initializeOrderedBulkOp = function(options) {
+  options = options || {};
+  options.promiseLibrary = this.s.promiseLibrary;
+  return ordered(this.s.topology, this, options);
+}
+
+define.classMethod('initializeOrderedBulkOp', {callback: false, promise:false, returns: [ordered.OrderedBulkOperation]});
+
+// Get write concern
+var writeConcern = function(target, db, col, options) {
+  if(options.w != null || options.j != null || options.fsync != null) {
+    var opts = {};
+    if(options.w != null) opts.w = options.w;
+    if(options.wtimeout != null) opts.wtimeout = options.wtimeout;
+    if(options.j != null) opts.j = options.j;
+    if(options.fsync != null) opts.fsync = options.fsync;
+    target.writeConcern = opts;
+  } else if(col.writeConcern.w != null || col.writeConcern.j != null || col.writeConcern.fsync != null) {
+    target.writeConcern = col.writeConcern;
+  } else if(db.writeConcern.w != null || db.writeConcern.j != null || db.writeConcern.fsync != null) {
+    target.writeConcern = db.writeConcern;
+  }
+
+  return target
+}
+
+// Figure out the read preference
+var getReadPreference = function(self, options, db, coll) {
+  var r = null
+  if(options.readPreference) {
+    r = options.readPreference
+  } else if(self.s.readPreference) {
+    r = self.s.readPreference
+  } else if(db.readPreference) {
+    r = db.readPreference;
+  }
+
+  if(r instanceof ReadPreference) {
+    options.readPreference = new CoreReadPreference(r.mode, r.tags);
+  } else if(typeof r == 'string') {
+    options.readPreference = new CoreReadPreference(r);
+  } else if(r && !(r instanceof ReadPreference) && typeof r == 'object') {
+    var mode = r.mode || r.preference;
+    if (mode && typeof mode == 'string') {
+      options.readPreference = new CoreReadPreference(mode, r.tags);
+    }
+  }
+
+  return options;
+}
+
+var testForFields = {
+    limit: 1, sort: 1, fields:1, skip: 1, hint: 1, explain: 1, snapshot: 1, timeout: 1, tailable: 1, tailableRetryInterval: 1
+  , numberOfRetries: 1, awaitdata: 1, awaitData: 1, exhaust: 1, batchSize: 1, returnKey: 1, maxScan: 1, min: 1, max: 1, showDiskLoc: 1
+  , comment: 1, raw: 1, readPreference: 1, partial: 1, read: 1, dbName: 1, oplogReplay: 1, connection: 1, maxTimeMS: 1, transforms: 1
+}
+
+module.exports = Collection;