diff --git a/benchmarks/index.js b/benchmarks/index.js
index 784e6dbf3..e4a7fd6c6 100644
--- a/benchmarks/index.js
+++ b/benchmarks/index.js
@@ -5,29 +5,29 @@
 
 'use strict';
 
-var DataSource = require('loopback-datasource-juggler').DataSource;
-var connector = require('..');
-var Benchmark = require('benchmark');
+const DataSource = require('loopback-datasource-juggler').DataSource;
+const connector = require('..');
+const Benchmark = require('benchmark');
 
-var ds = new DataSource(connector, {
+const ds = new DataSource(connector, {
   host: process.env.LB_HOST || '127.0.0.1',
   port: process.env.LB_PORT || 27017,
   database: process.env.LB_DB || 'strongloop',
 });
-var Todo = ds.define('Todo', {
+const Todo = ds.define('Todo', {
   content: {type: String},
 });
 
 // not critical for MongoDB, but may uncover inefficiencies in SQL connectors
 // https://github.com/strongloop/loopback-connector-mongodb/pull/124/files#r28435614
-var uniqVal = 0;
+let uniqVal = 0;
 
 function resetTestState() {
   uniqVal = 0;
   Todo.destroyAll();
 }
 
-var suite = new Benchmark.Suite();
+const suite = new Benchmark.Suite();
 suite
   .on('start', function() {
     console.log('#', new Date());
diff --git a/example/model.js b/example/model.js
index cf0fee007..9f0da980e 100644
--- a/example/model.js
+++ b/example/model.js
@@ -5,15 +5,15 @@
 
 'use strict';
 
-var g = require('strong-globalize')();
+const g = require('strong-globalize')();
 
-var DataSource = require('loopback-datasource-juggler').DataSource;
+const DataSource = require('loopback-datasource-juggler').DataSource;
 
-var config = require('rc')('loopback', {dev: {mongodb: {}}}).dev.mongodb;
+const config = require('rc')('loopback', {dev: {mongodb: {}}}).dev.mongodb;
 
-var ds = new DataSource(require('../'), config);
+const ds = new DataSource(require('../'), config);
 
-var Customer = ds.createModel('customer', {
+const Customer = ds.createModel('customer', {
   seq: {type: Number, id: true},
   name: String,
   emails: [{label: String, email: String}],
diff --git a/index.js b/index.js
index 54f52c8fd..b6ce0ae82 100644
--- a/index.js
+++ b/index.js
@@ -5,7 +5,7 @@
 
 'use strict';
 
-var SG = require('strong-globalize');
+const SG = require('strong-globalize');
 SG.SetRootDir(__dirname);
 
 module.exports = require('./lib/mongodb');
diff --git a/leak-detection/fixtures/todo.js b/leak-detection/fixtures/todo.js
index c84bc6aad..dabd9f8fc 100644
--- a/leak-detection/fixtures/todo.js
+++ b/leak-detection/fixtures/todo.js
@@ -5,15 +5,15 @@
 
 'use strict';
 
-var DataSource = require('loopback-datasource-juggler').DataSource;
-var connector = require('../..');
+const DataSource = require('loopback-datasource-juggler').DataSource;
+const connector = require('../..');
 
-var db = new DataSource(connector, {
+const db = new DataSource(connector, {
   host: process.env.LB_HOST || '127.0.0.1',
   port: process.env.LB_PORT || 27017,
   database: process.env.LB_DB || 'strongloop',
 });
-var Todo = db.define('Todo', {
+const Todo = db.define('Todo', {
   content: {type: String},
 });
 
diff --git a/leak-detection/leak-detector.test.js b/leak-detection/leak-detector.test.js
index e0bda911d..9c0e5e701 100644
--- a/leak-detection/leak-detector.test.js
+++ b/leak-detection/leak-detector.test.js
@@ -5,14 +5,14 @@
 
 'use strict';
 
-var memwatch;
+let memwatch;
 
 try {
   memwatch = require('@airbnb/node-memwatch');
 } catch (e) {
   memwatch = require('memwatch-next');
 }
-var sinon = require('sinon');
+const sinon = require('sinon');
 
 describe('leak detector', function() {
   before(function() {
@@ -21,18 +21,18 @@ describe('leak detector', function() {
   });
 
   it('should detect a basic leak', function(done) {
-    var test = this;
-    var iterations = 0;
-    var leaks = [];
-    var interval = setInterval(function() {
+    const test = this;
+    const iterations = 0;
+    const leaks = [];
+    const interval = setInterval(function() {
       if (test.iterations >= global.ITERATIONS || test.spy.called) {
         test.spy.called.should.be.True();
         clearInterval(interval);
         return done();
       }
       test.iterations++;
-      for (var i = 0; i < 1000000; i++) {
-        var str = 'leaky string';
+      for (let i = 0; i < 1000000; i++) {
+        const str = 'leaky string';
         leaks.push(str);
       }
     }, 0);
diff --git a/leak-detection/mongodb.test.js b/leak-detection/mongodb.test.js
index 7f6dd0bba..c15974af7 100644
--- a/leak-detection/mongodb.test.js
+++ b/leak-detection/mongodb.test.js
@@ -5,9 +5,9 @@
 
 'use strict';
 
-var memwatch = require('memwatch-next');
-var sinon = require('sinon');
-var Todo = require('./fixtures/todo');
+const memwatch = require('memwatch-next');
+const sinon = require('sinon');
+const Todo = require('./fixtures/todo');
 
 describe('mongodb', function() {
   before(function() {
@@ -26,12 +26,12 @@ describe('mongodb', function() {
   }
 
   function execute(ctx, func, options, done) {
-    var hasOptions = true;
+    let hasOptions = true;
     if (typeof options === 'function') {
       done = options;
       hasOptions = false;
     }
-    var interval = setInterval(function() {
+    const interval = setInterval(function() {
       if (ctx.iterations >= global.ITERATIONS || ctx.spy.called) {
         ctx.spy.called.should.be.False();
         clearInterval(interval);
diff --git a/lib/mongodb.js b/lib/mongodb.js
index 7b1fe4598..918b9cfd1 100644
--- a/lib/mongodb.js
+++ b/lib/mongodb.js
@@ -8,15 +8,15 @@
 /*!
  * Module dependencies
  */
-var bson = require('bson');
-var g = require('strong-globalize')();
-var mongodb = require('mongodb');
-var urlParser = require('mongodb/lib/url_parser');
-var util = require('util');
-var async = require('async');
-var Connector = require('loopback-connector').Connector;
-var debug = require('debug')('loopback:connector:mongodb');
-var Decimal128 = mongodb.Decimal128;
+const bson = require('bson');
+const g = require('strong-globalize')();
+const mongodb = require('mongodb');
+const urlParser = require('mongodb/lib/url_parser');
+const util = require('util');
+const async = require('async');
+const Connector = require('loopback-connector').Connector;
+const debug = require('debug')('loopback:connector:mongodb');
+const Decimal128 = mongodb.Decimal128;
 
 exports.ObjectID = ObjectID;
 /*!
@@ -56,8 +56,8 @@ function generateMongoDBURL(options) {
   options.hostname = options.hostname || options.host || '127.0.0.1';
   options.port = options.port || 27017;
   options.database = options.database || options.db || 'test';
-  var username = options.username || options.user;
-  var portUrl = '';
+  const username = options.username || options.user;
+  let portUrl = '';
   // only include port if not using mongodb+srv
   if (options.protocol !== 'mongodb+srv') {
     portUrl = ':' + options.port;
@@ -97,7 +97,7 @@ exports.initialize = function initializeDataSource(dataSource, callback) {
     return;
   }
 
-  var s = dataSource.settings;
+  const s = dataSource.settings;
 
   s.safe = s.safe !== false;
   s.w = s.w || 1;
@@ -206,7 +206,7 @@ util.inherits(MongoDB, Connector);
  * @param {Db} db The mongo DB object
  */
 MongoDB.prototype.connect = function(callback) {
-  var self = this;
+  const self = this;
   if (self.db) {
     process.nextTick(function() {
       if (callback) callback(null, self.db);
@@ -219,7 +219,7 @@ MongoDB.prototype.connect = function(callback) {
     });
   } else {
     // See https://github.com/mongodb/node-mongodb-native/blob/3.0.0/lib/mongo_client.js#L37
-    var validOptionNames = [
+    const validOptionNames = [
       'poolSize',
       'ssl',
       'sslValidate',
@@ -287,8 +287,8 @@ MongoDB.prototype.connect = function(callback) {
       'db',
     ];
 
-    var lbOptions = Object.keys(self.settings);
-    var validOptions = {};
+    const lbOptions = Object.keys(self.settings);
+    const validOptions = {};
     lbOptions.forEach(function(option) {
       if (validOptionNames.indexOf(option) > -1) {
         validOptions[option] = self.settings[option];
@@ -340,7 +340,7 @@ MongoDB.prototype.getDefaultIdType = function() {
  * @returns {String} collection name
  */
 MongoDB.prototype.collectionName = function(modelName) {
-  var modelClass = this._models[modelName];
+  const modelClass = this._models[modelName];
   if (modelClass.settings.mongodb) {
     modelName = modelClass.settings.mongodb.collection || modelName;
   }
@@ -356,7 +356,7 @@ MongoDB.prototype.collection = function(modelName) {
   if (!this.db) {
     throw new Error(g.f('{{MongoDB}} connection is not established'));
   }
-  var collectionName = this.collectionName(modelName);
+  const collectionName = this.collectionName(modelName);
   return this.db.collection(collectionName);
 };
 
@@ -370,10 +370,10 @@ MongoDB.prototype.fromDatabase = function(modelName, data) {
   if (!data) {
     return null;
   }
-  var modelInfo = this._models[modelName] || this.dataSource.modelBuilder.definitions[modelName];
-  var props = modelInfo.properties;
-  for (var p in props) {
-    var prop = props[p];
+  const modelInfo = this._models[modelName] || this.dataSource.modelBuilder.definitions[modelName];
+  const props = modelInfo.properties;
+  for (const p in props) {
+    const prop = props[p];
     if (prop && prop.type === Buffer) {
       if (data[p] instanceof mongodb.Binary) {
         // Convert the Binary into Buffer
@@ -413,7 +413,7 @@ MongoDB.prototype.fromDatabase = function(modelName, data) {
  */
 MongoDB.prototype.toDatabase = function(modelName, data) {
   const modelInstance = this._models[modelName].model;
-  var props = this._models[modelName].properties;
+  const props = this._models[modelName].properties;
 
   if (this.settings.enableGeoIndexing !== true) {
     visitAllProperties(data, modelInstance, coerceDecimalProperty);
@@ -422,8 +422,8 @@ MongoDB.prototype.toDatabase = function(modelName, data) {
     return data;
   }
 
-  for (var p in props) {
-    var prop = props[p];
+  for (const p in props) {
+    const prop = props[p];
     const isGeoPoint = data[p] && prop && prop.type && prop.type.name === 'GeoPoint';
     if (isGeoPoint) {
       data[p] = {
@@ -447,11 +447,11 @@ MongoDB.prototype.toDatabase = function(modelName, data) {
  * @param [...] params Parameters for the given command
  */
 MongoDB.prototype.execute = function(modelName, command) {
-  var self = this;
+  const self = this;
   // Get the parameters for the given command
-  var args = [].slice.call(arguments, 2);
+  const args = [].slice.call(arguments, 2);
   // The last argument must be a callback function
-  var callback = args[args.length - 1];
+  const callback = args[args.length - 1];
 
   // Topology is destroyed when the server is disconnected
   // Execute if DB is connected and functional otherwise connect/reconnect first
@@ -476,8 +476,8 @@ MongoDB.prototype.execute = function(modelName, command) {
   }
 
   function doExecute() {
-    var collection;
-    var context = Object.assign({}, {
+    let collection;
+    const context = Object.assign({}, {
       model: modelName,
       collection: collection,
       req: {
@@ -522,12 +522,12 @@ MongoDB.prototype.execute = function(modelName, command) {
 MongoDB.prototype.coerceId = function(modelName, id, options) {
   // See https://github.com/strongloop/loopback-connector-mongodb/issues/206
   if (id == null) return id;
-  var self = this;
-  var idValue = id;
-  var idName = self.idName(modelName);
+  const self = this;
+  let idValue = id;
+  const idName = self.idName(modelName);
 
   // Type conversion for id
-  var idProp = self.getPropertyDefinition(modelName, idName);
+  const idProp = self.getPropertyDefinition(modelName, idName);
   if (idProp && typeof idProp.type === 'function') {
     if (!(idValue instanceof idProp.type)) {
       idValue = idProp.type(id);
@@ -551,17 +551,17 @@ MongoDB.prototype.coerceId = function(modelName, id, options) {
  * @param {Function} [callback] The callback function
  */
 MongoDB.prototype.create = function(modelName, data, options, callback) {
-  var self = this;
+  const self = this;
   if (self.debug) {
     debug('create', modelName, data);
   }
-  var idValue = self.getIdValue(modelName, data);
-  var idName = self.idName(modelName);
+  let idValue = self.getIdValue(modelName, data);
+  const idName = self.idName(modelName);
 
   if (idValue === null) {
     delete data[idName]; // Allow MongoDB to generate the id
   } else {
-    var oid = self.coerceId(modelName, idValue, options); // Is it an Object ID?c
+    const oid = self.coerceId(modelName, idValue, options); // Is it an Object ID?c
     data._id = oid; // Set it to _id
     if (idName !== '_id') {
       delete data[idName];
@@ -597,14 +597,14 @@ MongoDB.prototype.create = function(modelName, data, options, callback) {
  * @param {Function} [callback] The callback function
  */
 MongoDB.prototype.save = function(modelName, data, options, callback) {
-  var self = this;
+  const self = this;
   if (self.debug) {
     debug('save', modelName, data);
   }
-  var idValue = self.getIdValue(modelName, data);
-  var idName = self.idName(modelName);
+  const idValue = self.getIdValue(modelName, data);
+  const idName = self.idName(modelName);
 
-  var oid = self.coerceId(modelName, idValue, options);
+  const oid = self.coerceId(modelName, idValue, options);
   data._id = oid;
   if (idName !== '_id') {
     delete data[idName];
@@ -623,7 +623,7 @@ MongoDB.prototype.save = function(modelName, data, options, callback) {
       debug('save.callback', modelName, err, result);
     }
 
-    var info = {};
+    const info = {};
     if (result && result.result) {
       // create result formats:
       //   { ok: 1, n: 1, upserted: [ [Object] ] }
@@ -653,7 +653,7 @@ MongoDB.prototype.save = function(modelName, data, options, callback) {
  *
  */
 MongoDB.prototype.exists = function(modelName, id, options, callback) {
-  var self = this;
+  const self = this;
   if (self.debug) {
     debug('exists', modelName, id);
   }
@@ -673,12 +673,12 @@ MongoDB.prototype.exists = function(modelName, id, options, callback) {
  * @param {Function} [callback] The callback function
  */
 MongoDB.prototype.find = function find(modelName, id, options, callback) {
-  var self = this;
+  const self = this;
   if (self.debug) {
     debug('find', modelName, id);
   }
-  var idName = self.idName(modelName);
-  var oid = self.coerceId(modelName, id, options);
+  const idName = self.idName(modelName);
+  const oid = self.coerceId(modelName, id, options);
   this.execute(modelName, 'findOne', {_id: oid}, function(err, data) {
     if (self.debug) {
       debug('find.callback', modelName, id, err, data);
@@ -705,11 +705,11 @@ Connector.defineAliases(MongoDB.prototype, 'find', 'findById');
  */
 MongoDB.prototype.parseUpdateData = function(modelName, data, options) {
   options = options || {};
-  var parsedData = {};
+  const parsedData = {};
 
-  var modelClass = this._models[modelName];
+  const modelClass = this._models[modelName];
 
-  var allowExtendedOperators = this.settings.allowExtendedOperators;
+  let allowExtendedOperators = this.settings.allowExtendedOperators;
   if (options.hasOwnProperty('allowExtendedOperators')) {
     allowExtendedOperators = options.allowExtendedOperators === true;
   } else if (
@@ -725,7 +725,7 @@ MongoDB.prototype.parseUpdateData = function(modelName, data, options) {
 
   if (allowExtendedOperators) {
     // Check for other operators and sanitize the data obj
-    var acceptedOperators = [
+    const acceptedOperators = [
       // Field operators
       '$currentDate',
       '$inc',
@@ -747,10 +747,10 @@ MongoDB.prototype.parseUpdateData = function(modelName, data, options) {
       '$bit',
     ];
 
-    var usedOperators = 0;
+    let usedOperators = 0;
 
     // each accepted operator will take its place on parsedData if defined
-    for (var i = 0; i < acceptedOperators.length; i++) {
+    for (let i = 0; i < acceptedOperators.length; i++) {
       if (data[acceptedOperators[i]]) {
         parsedData[acceptedOperators[i]] = data[acceptedOperators[i]];
         usedOperators++;
@@ -781,14 +781,14 @@ MongoDB.prototype.updateOrCreate = function updateOrCreate(
   options,
   callback
 ) {
-  var self = this;
+  const self = this;
   if (self.debug) {
     debug('updateOrCreate', modelName, data);
   }
 
-  var id = self.getIdValue(modelName, data);
-  var idName = self.idName(modelName);
-  var oid = self.coerceId(modelName, id, options);
+  const id = self.getIdValue(modelName, data);
+  const idName = self.idName(modelName);
+  const oid = self.coerceId(modelName, id, options);
   delete data[idName];
 
   data = self.toDatabase(modelName, data);
@@ -812,7 +812,7 @@ MongoDB.prototype.updateOrCreate = function updateOrCreate(
       if (self.debug) {
         debug('updateOrCreate.callback', modelName, id, err, result);
       }
-      var object = result && result.value;
+      const object = result && result.value;
       if (!err && !object) {
         // No result
         err = 'No ' + modelName + ' found for id ' + id;
@@ -824,7 +824,7 @@ MongoDB.prototype.updateOrCreate = function updateOrCreate(
         }
       }
 
-      var info;
+      let info;
       if (result && result.lastErrorObject) {
         info = {isNewInstance: !result.lastErrorObject.updatedExisting};
       } else {
@@ -849,9 +849,9 @@ MongoDB.prototype.updateOrCreate = function updateOrCreate(
 MongoDB.prototype.replaceOrCreate = function(modelName, data, options, cb) {
   if (this.debug) debug('replaceOrCreate', modelName, data);
 
-  var id = this.getIdValue(modelName, data);
-  var oid = this.coerceId(modelName, id, options);
-  var idName = this.idName(modelName);
+  const id = this.getIdValue(modelName, data);
+  const oid = this.coerceId(modelName, id, options);
+  const idName = this.idName(modelName);
   data._id = data[idName];
   delete data[idName];
   this.replaceWithOptions(modelName, oid, data, {upsert: true}, cb);
@@ -864,7 +864,7 @@ MongoDB.prototype.replaceOrCreate = function(modelName, data, options, cb) {
  * @param [callback] The callback function
  */
 MongoDB.prototype.destroy = function destroy(modelName, id, options, callback) {
-  var self = this;
+  const self = this;
   if (self.debug) {
     debug('delete', modelName, id);
   }
@@ -873,7 +873,7 @@ MongoDB.prototype.destroy = function destroy(modelName, id, options, callback) {
     if (self.debug) {
       debug('delete.callback', modelName, id, err, result);
     }
-    var res = result && result.result;
+    let res = result && result.result;
     if (res) {
       res = {count: res.n};
     }
@@ -904,24 +904,24 @@ function idIncluded(fields, idName) {
     // Excluded
     return false;
   }
-  for (var f in fields) {
+  for (const f in fields) {
     return !fields[f]; // If the fields has exclusion
   }
   return true;
 }
 
 MongoDB.prototype.buildWhere = function(modelName, where, options) {
-  var self = this;
-  var query = {};
+  const self = this;
+  const query = {};
   if (where === null || typeof where !== 'object') {
     return query;
   }
 
   where = sanitizeFilter(where, options);
 
-  var idName = self.idName(modelName);
+  const idName = self.idName(modelName);
   Object.keys(where).forEach(function(k) {
-    var cond = where[k];
+    let cond = where[k];
     if (k === 'and' || k === 'or' || k === 'nor') {
       if (Array.isArray(cond)) {
         cond = cond.map(function(c) {
@@ -935,12 +935,12 @@ MongoDB.prototype.buildWhere = function(modelName, where, options) {
     if (k === idName) {
       k = '_id';
     }
-    var propName = k;
+    let propName = k;
     if (k === '_id') {
       propName = idName;
     }
 
-    var prop = self.getPropertyDefinition(modelName, propName);
+    const prop = self.getPropertyDefinition(modelName, propName);
 
     const isDecimal = prop &&
       prop.mongodb && prop.mongodb.dataType &&
@@ -953,8 +953,8 @@ MongoDB.prototype.buildWhere = function(modelName, where, options) {
     // Convert property to database column name
     k = self.getDatabaseColumnName(modelName, k);
 
-    var spec = false;
-    var regexOptions = null;
+    let spec = false;
+    let regexOptions = null;
     if (cond && cond.constructor.name === 'Object') {
       regexOptions = cond.options;
       spec = Object.keys(cond)[0];
@@ -1021,12 +1021,12 @@ MongoDB.prototype.buildWhere = function(modelName, where, options) {
 };
 
 MongoDB.prototype.buildSort = function(modelName, order, options) {
-  var sort = {};
-  var idName = this.idName(modelName);
+  let sort = {};
+  const idName = this.idName(modelName);
 
-  var modelClass = this._models[modelName];
+  const modelClass = this._models[modelName];
 
-  var disableDefaultSort = false;
+  let disableDefaultSort = false;
   if (this.settings.hasOwnProperty('disableDefaultSort')) {
     disableDefaultSort = this.settings.disableDefaultSort;
   }
@@ -1038,20 +1038,20 @@ MongoDB.prototype.buildSort = function(modelName, order, options) {
   }
 
   if (!order && !disableDefaultSort) {
-    var idNames = this.idNames(modelName);
+    const idNames = this.idNames(modelName);
     if (idNames && idNames.length) {
       order = idNames;
     }
   }
   if (order) {
     order = sanitizeFilter(order, options);
-    var keys = order;
+    let keys = order;
     if (typeof keys === 'string') {
       keys = keys.split(',');
     }
-    for (var index = 0, len = keys.length; index < len; index++) {
-      var m = keys[index].match(/\s+(A|DE)SC$/);
-      var key = keys[index];
+    for (let index = 0, len = keys.length; index < len; index++) {
+      const m = keys[index].match(/\s+(A|DE)SC$/);
+      let key = keys[index];
       key = key.replace(/\s+(A|DE)SC$/, '').trim();
       if (key === idName) {
         key = '_id';
@@ -1098,10 +1098,10 @@ function buildNearFilter(query, params) {
   }
 
   params.forEach(function(near) {
-    var coordinates = {};
+    let coordinates = {};
 
     if (typeof near.near === 'string') {
-      var s = near.near.split(',');
+      const s = near.near.split(',');
       coordinates.lng = parseFloat(s[0]);
       coordinates.lat = parseFloat(s[1]);
     } else if (Array.isArray(near.near)) {
@@ -1111,11 +1111,11 @@ function buildNearFilter(query, params) {
       coordinates = near.near;
     }
 
-    var props = ['maxDistance', 'minDistance'];
+    const props = ['maxDistance', 'minDistance'];
     // use mongodb default unit 'meters' rather than 'miles'
-    var unit = near.unit || 'meters';
+    const unit = near.unit || 'meters';
 
-    var queryValue = {
+    const queryValue = {
       near: {
         $geometry: {
           coordinates: [coordinates.lng, coordinates.lat],
@@ -1130,15 +1130,16 @@ function buildNearFilter(query, params) {
       }
     });
 
-    var property;
+    let property;
 
     if (near.mongoKey) {
       // if mongoKey is an Array, set the $near query at the right depth, following the Array
       if (Array.isArray(near.mongoKey)) {
         property = query.where;
 
-        for (var i = 0; i < near.mongoKey.length; i++) {
-          var subKey = near.mongoKey[i];
+        let i;
+        for (i = 0; i < near.mongoKey.length; i++) {
+          const subKey = near.mongoKey[i];
 
           if (near.mongoKey.hasOwnProperty(i + 1)) {
             if (!property.hasOwnProperty(subKey)) {
@@ -1165,7 +1166,7 @@ function hasNearFilter(where) {
   // TODO: Optimize to return once a `near` key is found
   // instead of searching through everything
 
-  var isFound = false;
+  let isFound = false;
 
   searchForNear(where);
 
@@ -1188,7 +1189,7 @@ function hasNearFilter(where) {
       });
     } else if (typeof node === 'object') {
       Object.keys(node).forEach(function(key) {
-        var prop = node[key];
+        const prop = node[key];
 
         isFound = found(prop);
 
@@ -1214,7 +1215,7 @@ MongoDB.prototype.getDatabaseColumnName = function(model, propName) {
     return propName; // missing model properties?
   }
 
-  var prop = model.properties[propName] || {};
+  const prop = model.properties[propName] || {};
 
   // console.log('getDatabaseColumnName', propName, prop);
 
@@ -1255,8 +1256,8 @@ MongoDB.prototype.convertColumnNames = function(model, data, direction) {
     return data; // missing model properties?
   }
 
-  for (var propName in model.properties) {
-    var columnName = this.getDatabaseColumnName(model, propName);
+  for (const propName in model.properties) {
+    const columnName = this.getDatabaseColumnName(model, propName);
 
     // Copy keys/data if needed
     if (propName === columnName) {
@@ -1293,23 +1294,23 @@ MongoDB.prototype.fromDatabaseToPropertyNames = function(model, data) {
  * @param {Function} [callback] The callback function
  */
 MongoDB.prototype.all = function all(modelName, filter, options, callback) {
-  var self = this;
+  const self = this;
   if (self.debug) {
     debug('all', modelName, filter);
   }
   filter = filter || {};
-  var idName = self.idName(modelName);
-  var query = {};
+  const idName = self.idName(modelName);
+  let query = {};
   if (filter.where) {
     query = self.buildWhere(modelName, filter.where, options);
   }
-  var fields = filter.fields;
+  let fields = filter.fields;
 
   // Convert custom column names
   fields = self.fromPropertyToDatabaseNames(modelName, fields);
 
   if (fields) {
-    var findOpts = {projection: fieldsArrayToObj(fields)};
+    const findOpts = {projection: fieldsArrayToObj(fields)};
     this.execute(modelName, 'find', query, findOpts, processResponse);
   } else {
     this.execute(modelName, 'find', query, processResponse);
@@ -1320,14 +1321,14 @@ MongoDB.prototype.all = function all(modelName, filter, options, callback) {
       return callback(err);
     }
 
-    var collation = options && options.collation;
+    const collation = options && options.collation;
     if (collation) {
       cursor.collation(collation);
     }
 
     // don't apply sorting if dealing with a geo query
     if (!hasNearFilter(filter.where)) {
-      var order = self.buildSort(modelName, filter.order, options);
+      const order = self.buildSort(modelName, filter.order, options);
       cursor.sort(order);
     }
 
@@ -1340,8 +1341,8 @@ MongoDB.prototype.all = function all(modelName, filter, options, callback) {
       cursor.skip(filter.offset);
     }
 
-    var shouldSetIdValue = idIncluded(fields, idName);
-    var deleteMongoId = !shouldSetIdValue || idName !== '_id';
+    const shouldSetIdValue = idIncluded(fields, idName);
+    const deleteMongoId = !shouldSetIdValue || idName !== '_id';
 
     cursor.toArray(function(err, data) {
       if (self.debug) {
@@ -1350,7 +1351,7 @@ MongoDB.prototype.all = function all(modelName, filter, options, callback) {
       if (err) {
         return callback(err);
       }
-      var objs = data.map(function(o) {
+      const objs = data.map(function(o) {
         if (shouldSetIdValue) {
           self.setIdValue(modelName, o, o._id);
         }
@@ -1388,7 +1389,7 @@ MongoDB.prototype.destroyAll = function destroyAll(
   options,
   callback
 ) {
-  var self = this;
+  const self = this;
   if (self.debug) {
     debug('destroyAll', modelName, where);
   }
@@ -1404,7 +1405,7 @@ MongoDB.prototype.destroyAll = function destroyAll(
 
     if (self.debug) debug('destroyAll.callback', modelName, where, err, info);
 
-    var affectedCount = info.result ? info.result.n : undefined;
+    const affectedCount = info.result ? info.result.n : undefined;
 
     if (callback) {
       callback(err, {count: affectedCount});
@@ -1421,7 +1422,7 @@ MongoDB.prototype.destroyAll = function destroyAll(
  *
  */
 MongoDB.prototype.count = function count(modelName, where, options, callback) {
-  var self = this;
+  const self = this;
   if (self.debug) {
     debug('count', modelName, where);
   }
@@ -1447,7 +1448,7 @@ MongoDB.prototype.count = function count(modelName, where, options, callback) {
  */
 MongoDB.prototype.replaceById = function replace(modelName, id, data, options, cb) {
   if (this.debug) debug('replace', modelName, id, data);
-  var oid = this.coerceId(modelName, id, options);
+  const oid = this.coerceId(modelName, id, options);
   this.replaceWithOptions(modelName, oid, data, {upsert: false}, function(
     err,
     data
@@ -1457,8 +1458,8 @@ MongoDB.prototype.replaceById = function replace(modelName, id, data, options, c
 };
 
 function errorIdNotFoundForReplace(idValue) {
-  var msg = 'Could not replace. Object with id ' + idValue + ' does not exist!';
-  var error = new Error(msg);
+  const msg = 'Could not replace. Object with id ' + idValue + ' does not exist!';
+  const error = new Error(msg);
   error.statusCode = error.status = 404;
   return error;
 }
@@ -1472,8 +1473,8 @@ function errorIdNotFoundForReplace(idValue) {
  * @callback {Function} [cb] Callback function
  */
 MongoDB.prototype.replaceWithOptions = function(modelName, id, data, options, cb) {
-  var self = this;
-  var idName = self.idName(modelName);
+  const self = this;
+  const idName = self.idName(modelName);
   delete data[idName];
   this.execute(modelName, 'replaceOne', {_id: id}, data, options, function(
     err,
@@ -1481,8 +1482,8 @@ MongoDB.prototype.replaceWithOptions = function(modelName, id, data, options, cb
   ) {
     debug('updateWithOptions.callback', modelName, {_id: id}, data, err, info);
     if (err) return cb && cb(err);
-    var result;
-    var cbInfo = {};
+    let result;
+    const cbInfo = {};
     if (info.result && info.result.n == 1) {
       result = data;
       delete result._id;
@@ -1520,7 +1521,7 @@ MongoDB.prototype.updateAttributes = function updateAttrs(
   options,
   cb
 ) {
-  var self = this;
+  const self = this;
 
   data = self.toDatabase(modelName, data || {});
 
@@ -1540,8 +1541,8 @@ MongoDB.prototype.updateAttributes = function updateAttrs(
     return;
   }
 
-  var oid = self.coerceId(modelName, id, options);
-  var idName = this.idName(modelName);
+  const oid = self.coerceId(modelName, id, options);
+  const idName = this.idName(modelName);
 
   this.execute(
     modelName,
@@ -1557,7 +1558,7 @@ MongoDB.prototype.updateAttributes = function updateAttrs(
       if (self.debug) {
         debug('updateAttributes.callback', modelName, id, err, result);
       }
-      var object = result && result.value;
+      const object = result && result.value;
       if (!err && !object) {
         // No result
         err = errorIdNotFoundForUpdate(modelName, id);
@@ -1574,8 +1575,8 @@ MongoDB.prototype.updateAttributes = function updateAttrs(
 };
 
 function errorIdNotFoundForUpdate(modelvalue, idValue) {
-  var msg = 'No ' + modelvalue + ' found for id ' + idValue;
-  var error = new Error(msg);
+  const msg = 'No ' + modelvalue + ' found for id ' + idValue;
+  const error = new Error(msg);
   error.statusCode = error.status = 404;
   return error;
 }
@@ -1594,11 +1595,11 @@ MongoDB.prototype.update = MongoDB.prototype.updateAll = function updateAll(
   options,
   cb
 ) {
-  var self = this;
+  const self = this;
   if (self.debug) {
     debug('updateAll', modelName, where, data);
   }
-  var idName = this.idName(modelName);
+  const idName = this.idName(modelName);
 
   where = self.buildWhere(modelName, where, options);
 
@@ -1620,7 +1621,7 @@ MongoDB.prototype.update = MongoDB.prototype.updateAll = function updateAll(
       if (self.debug)
         debug('updateAll.callback', modelName, where, data, err, info);
 
-      var affectedCount = info.result ? info.result.n : undefined;
+      const affectedCount = info.result ? info.result.n : undefined;
 
       if (cb) {
         cb(err, {count: affectedCount});
@@ -1654,7 +1655,7 @@ MongoDB.prototype.disconnect = function(cb) {
  * @param {Function} [cb] The callback function
  */
 MongoDB.prototype.autoupdate = function(models, cb) {
-  var self = this;
+  const self = this;
   if (self.db) {
     if (self.debug) {
       debug('autoupdate');
@@ -1670,18 +1671,18 @@ MongoDB.prototype.autoupdate = function(models, cb) {
 
     models = models || Object.keys(self._models);
 
-    var enableGeoIndexing = this.settings.enableGeoIndexing === true;
+    const enableGeoIndexing = this.settings.enableGeoIndexing === true;
 
     async.each(
       models,
       function(modelName, modelCallback) {
-        var indexes = self._models[modelName].settings.indexes || [];
-        var indexList = [];
-        var index = {};
-        var options = {};
+        const indexes = self._models[modelName].settings.indexes || [];
+        let indexList = [];
+        let index = {};
+        let options = {};
 
         if (typeof indexes === 'object') {
-          for (var indexName in indexes) {
+          for (const indexName in indexes) {
             index = indexes[indexName];
             if (index.keys) {
               // The index object has keys
@@ -1700,9 +1701,9 @@ MongoDB.prototype.autoupdate = function(models, cb) {
         } else if (Array.isArray(indexes)) {
           indexList = indexList.concat(indexes);
         }
-        var properties = self._models[modelName].properties;
+        const properties = self._models[modelName].properties;
         /* eslint-disable one-var */
-        for (var p in properties) {
+        for (const p in properties) {
           if (properties[p].index) {
             index = {};
             index[p] = 1; // Add the index key
@@ -1734,7 +1735,7 @@ MongoDB.prototype.autoupdate = function(models, cb) {
               properties[p].type &&
               properties[p].type.name === 'GeoPoint'
             ) {
-              var indexType =
+              const indexType =
                 typeof properties[p].index === 'string' ?
                   properties[p].index :
                   '2dsphere';
@@ -1789,7 +1790,7 @@ MongoDB.prototype.autoupdate = function(models, cb) {
  * @param {Function} [cb] The callback function
  */
 MongoDB.prototype.automigrate = function(models, cb) {
-  var self = this;
+  const self = this;
   if (self.db) {
     if (self.debug) {
       debug('automigrate');
@@ -1809,7 +1810,7 @@ MongoDB.prototype.automigrate = function(models, cb) {
     async.eachSeries(
       models,
       function(modelName, modelCallback) {
-        var collectionName = self.collectionName(modelName);
+        const collectionName = self.collectionName(modelName);
         if (self.debug) {
           debug('drop collection %s for model %s', collectionName, modelName);
         }
@@ -1855,7 +1856,7 @@ MongoDB.prototype.automigrate = function(models, cb) {
 };
 
 MongoDB.prototype.ping = function(cb) {
-  var self = this;
+  const self = this;
   if (self.db) {
     this.db.collection('dummy').findOne({_id: 1}, cb);
   } else {
@@ -1881,9 +1882,9 @@ MongoDB.prototype.isObjectIDProperty = function(modelName, prop, value, options)
   ) {
     return true;
   } else if ('string' === typeof value) {
-    var settings = this._models[modelName] && this._models[modelName].settings;
+    const settings = this._models[modelName] && this._models[modelName].settings;
     options = options || {};
-    var strict =
+    const strict =
       (settings && settings.strictObjectIDCoercion) ||
       this.settings.strictObjectIDCoercion ||
       options.strictObjectIDCoercion;
@@ -1922,20 +1923,20 @@ exports.sanitizeFilter = sanitizeFilter;
  * @param {Function} [callback] The callback function
  */
 function optimizedFindOrCreate(modelName, filter, data, options, callback) {
-  var self = this;
+  const self = this;
   if (self.debug) {
     debug('findOrCreate', modelName, filter, data);
   }
 
   if (!callback) callback = options;
 
-  var idValue = self.getIdValue(modelName, data);
-  var idName = self.idName(modelName);
+  const idValue = self.getIdValue(modelName, data);
+  const idName = self.idName(modelName);
 
   if (idValue == null) {
     delete data[idName]; // Allow MongoDB to generate the id
   } else {
-    var oid = self.coerceId(modelName, idValue, options); // Is it an Object ID?
+    const oid = self.coerceId(modelName, idValue, options); // Is it an Object ID?
     data._id = oid; // Set it to _id
     if (idName !== '_id') {
       delete data[idName];
@@ -1943,10 +1944,10 @@ function optimizedFindOrCreate(modelName, filter, data, options, callback) {
   }
 
   filter = filter || {};
-  var query = {};
+  let query = {};
   if (filter.where) {
     if (filter.where[idName]) {
-      var id = filter.where[idName];
+      let id = filter.where[idName];
       delete filter.where[idName];
       id = self.coerceId(modelName, id, options);
       filter.where._id = id;
@@ -1954,9 +1955,9 @@ function optimizedFindOrCreate(modelName, filter, data, options, callback) {
     query = self.buildWhere(modelName, filter.where, options);
   }
 
-  var sort = self.buildSort(modelName, filter.order, options);
+  const sort = self.buildSort(modelName, filter.order, options);
 
-  var projection = fieldsArrayToObj(filter.fields);
+  const projection = fieldsArrayToObj(filter.fields);
 
   this.collection(modelName).findOneAndUpdate(
     query,
@@ -1970,8 +1971,8 @@ function optimizedFindOrCreate(modelName, filter, data, options, callback) {
         return callback(err);
       }
 
-      var value = result.value;
-      var created = !!result.lastErrorObject.upserted;
+      let value = result.value;
+      const created = !!result.lastErrorObject.upserted;
 
       if (created && (value == null || Object.keys(value).length == 0)) {
         value = data;
diff --git a/lib/test-utils.js b/lib/test-utils.js
index 67642cfce..95bdbbd0e 100644
--- a/lib/test-utils.js
+++ b/lib/test-utils.js
@@ -9,18 +9,18 @@ exports.getDistanceBetweenPoints = function getDistanceBetweenPoints(
   point1,
   point2
 ) {
-  var R = 6371; // Radius of the earth in km
-  var dLat = deg2rad(point2.lat - point1.lat); // deg2rad below
-  var dLon = deg2rad(point2.lng - point1.lng);
-  var a =
+  const R = 6371; // Radius of the earth in km
+  const dLat = deg2rad(point2.lat - point1.lat); // deg2rad below
+  const dLon = deg2rad(point2.lng - point1.lng);
+  const a =
     Math.sin(dLat / 2) * Math.sin(dLat / 2) +
     Math.cos(deg2rad(point1.lat)) *
       Math.cos(deg2rad(point2.lat)) *
       Math.sin(dLon / 2) *
       Math.sin(dLon / 2);
 
-  var c = 2 * Math.atan2(Math.sqrt(a), Math.sqrt(1 - a));
-  var d = R * c; // Distance in km
+  const c = 2 * Math.atan2(Math.sqrt(a), Math.sqrt(1 - a));
+  const d = R * c; // Distance in km
 
   return d;
 };
diff --git a/package.json b/package.json
index 20db5abc2..01c9c4c32 100644
--- a/package.json
+++ b/package.json
@@ -38,7 +38,7 @@
     "benchmark": "^2.1.4",
     "bluebird": "^3.5.4",
     "eslint": "^5.1.0",
-    "eslint-config-loopback": "^10.0.0",
+    "eslint-config-loopback": "^13.0.0",
     "juggler-v3": "file:./deps/juggler-v3",
     "juggler-v4": "file:./deps/juggler-v4",
     "loopback-datasource-juggler": "^3.0.0 || ^4.0.0",
diff --git a/test/connector-functions.test.js b/test/connector-functions.test.js
index f28fd51b4..2c513d625 100644
--- a/test/connector-functions.test.js
+++ b/test/connector-functions.test.js
@@ -6,10 +6,10 @@
 'use strict';
 
 // This test written in mocha+should.js
-var should = require('./init.js');
+const should = require('./init.js');
 
 describe('connector function - findById', function() {
-  var db, TestAlias, sampleId;
+  let db, TestAlias, sampleId;
   before(function(done) {
     db = global.getDataSource();
     TestAlias = db.define('TestAlias', {foo: {type: String}});
diff --git a/test/decimal.test.js b/test/decimal.test.js
index 67badbeff..f8efac793 100644
--- a/test/decimal.test.js
+++ b/test/decimal.test.js
@@ -9,12 +9,12 @@ require('./init.js');
 const promisify = require('bluebird').promisify;
 const Decimal128 = require('mongodb').Decimal128;
 
-var db, OrderDecimal;
+let db, OrderDecimal;
 
 describe('model with decimal property', function() {
   before(function(done) {
     db = global.getDataSource();
-    var propertyDef = {
+    const propertyDef = {
       count: {
         type: String,
         mongodb: {
@@ -118,14 +118,14 @@ describe('model with decimal property', function() {
           updateOnLoad: true,
         });
 
-        var createData = {
+        const createData = {
           'randomReview': [
             '3.5',
             '4.5',
             '4.0',
           ],
         };
-        var updateData = {
+        const updateData = {
           'randomReview': [
             '5.5',
             '5.5',
diff --git a/test/id.test.js b/test/id.test.js
index 6b7ffd2cf..c7b218b73 100644
--- a/test/id.test.js
+++ b/test/id.test.js
@@ -6,10 +6,10 @@
 'use strict';
 
 require('./init.js');
-var ds = global.getDataSource();
+const ds = global.getDataSource();
 
 describe('mongodb custom id name', function() {
-  var Customer = ds.createModel(
+  const Customer = ds.createModel(
     'customer',
     {
       seq: {type: Number, id: true},
@@ -66,7 +66,7 @@ describe('mongodb custom id name', function() {
 });
 
 describe('mongodb string id', function() {
-  var Customer = ds.createModel(
+  const Customer = ds.createModel(
     'customer2',
     {
       seq: {type: String, id: true},
@@ -76,7 +76,7 @@ describe('mongodb string id', function() {
     },
     {forceId: false}
   );
-  var customer1, customer2;
+  let customer1, customer2;
 
   before(function(done) {
     Customer.deleteAll(done);
@@ -93,7 +93,7 @@ describe('mongodb string id', function() {
       function(err, customer) {
         customer.seq.should.equal('1');
         customer1 = customer;
-        var customer2Id = new ds.ObjectID().toString();
+        const customer2Id = new ds.ObjectID().toString();
         Customer.create(
           {
             seq: customer2Id,
@@ -140,7 +140,7 @@ describe('mongodb string id', function() {
 });
 
 describe('mongodb default id type', function() {
-  var Account = ds.createModel(
+  const Account = ds.createModel(
     'account',
     {
       seq: {id: true, generated: true},
@@ -155,7 +155,7 @@ describe('mongodb default id type', function() {
     Account.deleteAll(done);
   });
 
-  var id;
+  let id;
   it('should generate id value for create', function(done) {
     Account.create(
       {
@@ -197,7 +197,7 @@ describe('mongodb default id type', function() {
 });
 
 describe('mongodb default id name', function() {
-  var Customer1 = ds.createModel(
+  const Customer1 = ds.createModel(
     'customer1',
     {name: String, emails: [String], age: Number},
     {forceId: false}
diff --git a/test/init.js b/test/init.js
index d114969e9..5311bf2d5 100644
--- a/test/init.js
+++ b/test/init.js
@@ -7,11 +7,11 @@
 
 module.exports = require('should');
 
-var juggler = require('loopback-datasource-juggler');
-var DataSource = juggler.DataSource;
+const juggler = require('loopback-datasource-juggler');
+let DataSource = juggler.DataSource;
 
-var TEST_ENV = process.env.TEST_ENV || 'test';
-var config = require('rc')('loopback', {test: {mongodb: {}}})[TEST_ENV]
+const TEST_ENV = process.env.TEST_ENV || 'test';
+let config = require('rc')('loopback', {test: {mongodb: {}}})[TEST_ENV]
   .mongodb;
 
 config = {
@@ -25,7 +25,7 @@ config = {
 
 global.config = config;
 
-var db;
+let db;
 global.getDataSource = global.getSchema = function(customConfig, customClass) {
   const ctor = customClass || DataSource;
   db = new ctor(require('../'), customConfig || config);
@@ -38,7 +38,7 @@ global.getDataSource = global.getSchema = function(customConfig, customClass) {
 
 global.resetDataSourceClass = function(ctor) {
   DataSource = ctor || juggler.DataSource;
-  var promise = db ? db.disconnect() : Promise.resolve();
+  const promise = db ? db.disconnect() : Promise.resolve();
   db = undefined;
   return promise;
 };
diff --git a/test/mongodb.test.js b/test/mongodb.test.js
index dec88b771..c8877f933 100644
--- a/test/mongodb.test.js
+++ b/test/mongodb.test.js
@@ -6,16 +6,16 @@
 'use strict';
 
 // This test written in mocha+should.js
-var semver = require('semver');
-var should = require('./init.js');
-var testUtils = require('../lib/test-utils');
-var async = require('async');
-var sinon = require('sinon');
-var sanitizeFilter = require('../lib/mongodb').sanitizeFilter;
+const semver = require('semver');
+const should = require('./init.js');
+const testUtils = require('../lib/test-utils');
+const async = require('async');
+const sinon = require('sinon');
+const sanitizeFilter = require('../lib/mongodb').sanitizeFilter;
 
-var GeoPoint = require('loopback-datasource-juggler').GeoPoint;
+const GeoPoint = require('loopback-datasource-juggler').GeoPoint;
 
-var Superhero,
+let Superhero,
   User,
   Post,
   Product,
@@ -34,12 +34,12 @@ var Superhero,
 
 describe('lazyConnect', function() {
   it('should skip connect phase (lazyConnect = true)', function(done) {
-    var ds = global.getDataSource({
+    const ds = global.getDataSource({
       host: '127.0.0.1',
       port: 4,
       lazyConnect: true,
     });
-    var errTimeout = setTimeout(function() {
+    const errTimeout = setTimeout(function() {
       done();
     }, 2000);
 
@@ -50,7 +50,7 @@ describe('lazyConnect', function() {
   });
 
   it('should report connection error (lazyConnect = false)', function(done) {
-    var ds = global.getDataSource({
+    const ds = global.getDataSource({
       host: '127.0.0.1',
       port: 4,
       lazyConnect: false,
@@ -65,7 +65,7 @@ describe('lazyConnect', function() {
   });
 
   it('should connect on execute (lazyConnect = true)', function(done) {
-    var ds = global.getDataSource({
+    const ds = global.getDataSource({
       host: '127.0.0.1',
       port: global.config.port,
       lazyConnect: true,
@@ -90,7 +90,7 @@ describe('lazyConnect', function() {
   });
 
   it('should reconnect on execute when disconnected (lazyConnect = true)', function(done) {
-    var ds = global.getDataSource({
+    const ds = global.getDataSource({
       host: '127.0.0.1',
       port: global.config.port,
       lazyConnect: true,
@@ -108,7 +108,7 @@ describe('lazyConnect', function() {
       {value: 'test value'},
       function(err, success) {
         if (err) done(err);
-        var id = success.insertedId;
+        const id = success.insertedId;
         ds.connector.should.have.property('db');
         ds.connector.db.should.have.property('topology');
         ds.connector.db.topology.should.have.property('isDestroyed');
@@ -358,7 +358,7 @@ describe('mongodb connector', function() {
     });
 
     it('should report connection errors with invalid config', function(done) {
-      var ds = global.getDataSource({
+      const ds = global.getDataSource({
         host: 'localhost',
         port: 4, // unassigned by IANA
       });
@@ -371,10 +371,10 @@ describe('mongodb connector', function() {
     });
 
     it('ignores invalid option', function(done) {
-      var configWithInvalidOption = Object.assign({}, global.config, {
+      const configWithInvalidOption = Object.assign({}, global.config, {
         invalidOption: 'invalid',
       });
-      var ds = global.getDataSource(configWithInvalidOption);
+      const ds = global.getDataSource(configWithInvalidOption);
       ds.ping(function(err) {
         if (err) return done(err);
         ds.disconnect(done);
@@ -382,9 +382,9 @@ describe('mongodb connector', function() {
     });
 
     it('accepts database from the url', function(done) {
-      var cfg = JSON.parse(JSON.stringify(global.config));
+      const cfg = JSON.parse(JSON.stringify(global.config));
       delete cfg.database;
-      var ds = global.getDataSource(cfg);
+      const ds = global.getDataSource(cfg);
       ds.ping(function(err) {
         if (err) return done(err);
         ds.disconnect(done);
@@ -392,13 +392,13 @@ describe('mongodb connector', function() {
     });
 
     it('should prioritize to the database given in the url property', function(done) {
-      var cfg = JSON.parse(JSON.stringify(global.config));
-      var testDb = 'lb-ds-overriden-test-1';
+      const cfg = JSON.parse(JSON.stringify(global.config));
+      const testDb = 'lb-ds-overriden-test-1';
       cfg.url = 'mongodb://' + cfg.host + ':' + cfg.port + '/' + testDb;
-      var ds = global.getDataSource(cfg);
+      const ds = global.getDataSource(cfg);
       ds.once('connected', function() {
-        var db = ds.connector.db;
-        var validationError = null;
+        const db = ds.connector.db;
+        let validationError = null;
         try {
           db.should.have.property('databaseName', testDb); // check the db name in the db instance
         } catch (err) {
@@ -418,7 +418,7 @@ describe('mongodb connector', function() {
   });
 
   describe('order filters', function() {
-    var data = [
+    const data = [
       {
         id: 1,
         title: 'Senior Software Developer',
@@ -460,13 +460,13 @@ describe('mongodb connector', function() {
 
     context('using buildSort directly', function() {
       it('sort in descending order', function(done) {
-        var sort = db.connector.buildSort('Employee', 'id DESC');
+        const sort = db.connector.buildSort('Employee', 'id DESC');
         sort.should.have.property('_id');
         sort._id.should.equal(-1);
         done();
       });
       it('sort in ascending order', function(done) {
-        var sort = db.connector.buildSort('Employee', 'id ASC');
+        const sort = db.connector.buildSort('Employee', 'id ASC');
         sort.should.have.property('_id');
         sort._id.should.equal(1);
         done();
@@ -505,7 +505,7 @@ describe('mongodb connector', function() {
         .collection('User')
         .indexInformation(function(err, result) {
           /* eslint-disable camelcase */
-          var indexes = {
+          const indexes = {
             _id_: [['_id', 1]],
             name_age_index: [['name', 1], ['age', -1]],
             age_index: [['age', -1]],
@@ -523,7 +523,7 @@ describe('mongodb connector', function() {
     db.automigrate('Superhero', function() {
       db.connector.db.collection('sh').indexInformation(function(err, result) {
         /* eslint-disable camelcase */
-        var indexes = {
+        const indexes = {
           _id_: [['_id', 1]],
           geojson_location_geometry: [['location.geometry', '2dsphere']],
           power_1: [['power', 1]],
@@ -542,7 +542,7 @@ describe('mongodb connector', function() {
     db.automigrate('Category', function() {
       db.connector.db.collection('Category').indexes(function(err, result) {
         if (err) return done(err);
-        var indexes = [
+        const indexes = [
           {name: '_id_', key: {_id: 1}},
           {name: 'title_1', key: {title: 1}},
           {name: 'title_case_insensitive', key: {title: 1}, collation: {locale: 'en', strength: 1}},
@@ -660,7 +660,7 @@ describe('mongodb connector', function() {
   });
 
   it('all should return object (with `_id` as defined id) with an _id instanceof ObjectID', function(done) {
-    var post = new PostWithObjectId({title: 'a', content: 'AAA'});
+    const post = new PostWithObjectId({title: 'a', content: 'AAA'});
     post.save(function(err, post) {
       PostWithObjectId.all({where: {title: 'a'}}, function(err, posts) {
         should.not.exist(err);
@@ -676,7 +676,7 @@ describe('mongodb connector', function() {
   });
 
   it('all return should honor filter.fields, with `_id` as defined id', function(done) {
-    var post = new PostWithObjectId({title: 'a', content: 'AAA'});
+    const post = new PostWithObjectId({title: 'a', content: 'AAA'});
     post.save(function(err, post) {
       PostWithObjectId.all(
         {fields: ['title'], where: {title: 'a'}},
@@ -689,12 +689,13 @@ describe('mongodb connector', function() {
           should.not.exist(post._id);
 
           done();
-        });
+        }
+      );
     });
   });
 
   it('all return should honor filter.fields with `_id` selected', function(done) {
-    var post = new PostWithObjectId({title: 'a', content: 'AAA'});
+    const post = new PostWithObjectId({title: 'a', content: 'AAA'});
     post.save(function(err, post) {
       PostWithObjectId.all(
         {fields: ['_id', 'content'], where: {title: 'a'}},
@@ -908,8 +909,8 @@ describe('mongodb connector', function() {
   });
 
   it('should invoke hooks', function(done) {
-    var events = [];
-    var connector = Post.getDataSource().connector;
+    const events = [];
+    const connector = Post.getDataSource().connector;
     connector.observe('before execute', function(ctx, next) {
       ctx.req.command.should.be.String();
       ctx.req.params.should.be.Array();
@@ -1140,7 +1141,7 @@ describe('mongodb connector', function() {
       });
     });
 
-    var describeMongo26 = describe;
+    let describeMongo26 = describe;
     if (
       process.env.MONGODB_VERSION &&
       !semver.satisfies(process.env.MONGODB_VERSION, '~2.6.0')
@@ -1312,7 +1313,7 @@ describe('mongodb connector', function() {
 
       it('should be possible to enable using options - even if globally disabled', function(done) {
         User.dataSource.settings.allowExtendedOperators = false;
-        var options = {allowExtendedOperators: true};
+        const options = {allowExtendedOperators: true};
         User.create({name: 'Al', age: 31, email: 'al@strongloop'}, function(
           err1,
           createdusers1
@@ -1343,7 +1344,7 @@ describe('mongodb connector', function() {
 
       it('should be possible to disable using options - even if globally disabled', function(done) {
         User.dataSource.settings.allowExtendedOperators = true;
-        var options = {allowExtendedOperators: false};
+        const options = {allowExtendedOperators: false};
         User.create({name: 'Al', age: 31, email: 'al@strongloop'}, function(
           err1,
           createdusers1
@@ -1667,7 +1668,7 @@ describe('mongodb connector', function() {
     Product.create(
       {name: 'bread', price: 100, pricehistory: [{'2014-11-11': 90}]},
       function(err, product) {
-        var newattributes = {
+        const newattributes = {
           $set: {description: 'goes well with butter'},
           $addToSet: {pricehistory: {'2014-12-12': 110}},
         };
@@ -1746,7 +1747,7 @@ describe('mongodb connector', function() {
         pricehistory: [{'2014-11-11': 90}, {'2014-10-10': 80}],
       },
       function(err, product) {
-        var newattributes = {
+        const newattributes = {
           $set: {description: 'goes well with butter'},
           $addToSet: {pricehistory: {'2014-12-12': 110}},
         };
@@ -1781,7 +1782,7 @@ describe('mongodb connector', function() {
         ],
       },
       function(err, product) {
-        var newattributes = {
+        const newattributes = {
           $set: {description: 'goes well with butter'},
           $addToSet: {pricehistory: 1},
         };
@@ -1845,7 +1846,7 @@ describe('mongodb connector', function() {
     Product.create(
       {name: 'bread', price: 100, pricehistory: [70, 80, 90, 100]},
       function(err, product) {
-        var newattributes = {
+        const newattributes = {
           $set: {description: 'goes well with butter'},
           $pull: {pricehistory: {$gte: 90}},
         };
@@ -1895,7 +1896,7 @@ describe('mongodb connector', function() {
     Product.create(
       {name: 'bread', price: 100, pricehistory: [70, 80, 90, 100]},
       function(err, product) {
-        var newattributes = {
+        const newattributes = {
           $set: {description: 'goes well with butter'},
           $pullAll: {pricehistory: [80, 100]},
         };
@@ -1950,7 +1951,7 @@ describe('mongodb connector', function() {
         pricehistory: [{'2014-11-11': 90}, {'2014-10-10': 80}],
       },
       function(err, product) {
-        var newattributes = {
+        const newattributes = {
           $set: {description: 'goes well with butter'},
           $push: {pricehistory: {'2014-10-10': 80}},
         };
@@ -2177,7 +2178,7 @@ describe('mongodb connector', function() {
   });
 
   it('updateOrCreate should create a new instance if it does not exist', function(done) {
-    var post = {id: '123', title: 'a', content: 'AAA'};
+    const post = {id: '123', title: 'a', content: 'AAA'};
     Post.updateOrCreate(post, function(err, p) {
       should.not.exist(err);
       p.title.should.be.equal(post.title);
@@ -2239,7 +2240,7 @@ describe('mongodb connector', function() {
   });
 
   it('save should create a new instance if it does not exist', function(done) {
-    var post = new Post({id: '123', title: 'a', content: 'AAA'});
+    const post = new Post({id: '123', title: 'a', content: 'AAA'});
     post.save(post, function(err, p) {
       should.not.exist(err);
       p.title.should.be.equal(post.title);
@@ -2258,7 +2259,7 @@ describe('mongodb connector', function() {
     });
   });
   it('all should return object with an id, which is instanceof ObjectID, but not mongodb _id', function(done) {
-    var post = new Post({title: 'a', content: 'AAA'});
+    const post = new Post({title: 'a', content: 'AAA'});
     post.save(function(err, post) {
       Post.all({where: {title: 'a'}}, function(err, posts) {
         should.not.exist(err);
@@ -2275,7 +2276,7 @@ describe('mongodb connector', function() {
   });
 
   it('all return should honor filter.fields', function(done) {
-    var post = new Post({title: 'b', content: 'BBB'});
+    const post = new Post({title: 'b', content: 'BBB'});
     post.save(function(err, post) {
       db.connector.all(
         'Post',
@@ -2297,8 +2298,8 @@ describe('mongodb connector', function() {
   });
 
   it('create should convert id from ObjectID to string', function(done) {
-    var oid = new db.ObjectID();
-    var sid = oid.toString();
+    const oid = new db.ObjectID();
+    const sid = oid.toString();
     PostWithStringId.create({id: oid, title: 'c', content: 'CCC'}, function(
       err,
       post
@@ -2315,8 +2316,8 @@ describe('mongodb connector', function() {
   });
 
   it('create should convert id from string to ObjectID', function(done) {
-    var oid = new db.ObjectID();
-    var sid = oid.toString();
+    const oid = new db.ObjectID();
+    const sid = oid.toString();
     Post.create({id: sid, title: 'c', content: 'CCC'}, function(err, post) {
       post.id.should.be.an.instanceOf(db.ObjectID);
       Post.findById(sid, function(err, post) {
@@ -2351,7 +2352,7 @@ describe('mongodb connector', function() {
   });
 
   it('create should support renamed column names (using property syntax first)', function(done) {
-    var oid = new db.ObjectID().toString();
+    const oid = new db.ObjectID().toString();
     PostWithStringId.create({id: oid, title: 'c', content: 'CCC'}, function(
       err,
       post
@@ -2372,7 +2373,7 @@ describe('mongodb connector', function() {
   });
 
   it('create should support renamed column names (using db syntax first)', function(done) {
-    var oid = new db.ObjectID().toString();
+    const oid = new db.ObjectID().toString();
     PostWithStringIdAndRenamedColumns.create(
       {
         id: oid,
@@ -2397,10 +2398,10 @@ describe('mongodb connector', function() {
   });
 
   describe('geo queries', function() {
-    var geoDb, PostWithLocation, createLocationPost;
+    let geoDb, PostWithLocation, createLocationPost;
 
     before(function() {
-      var config = JSON.parse(JSON.stringify(global.config)); // clone config
+      const config = JSON.parse(JSON.stringify(global.config)); // clone config
       config.enableGeoIndexing = true;
 
       geoDb = global.getDataSource(config);
@@ -2410,7 +2411,7 @@ describe('mongodb connector', function() {
         location: {type: GeoPoint, index: true},
       });
       createLocationPost = function(far) {
-        var point;
+        let point;
         if (far) {
           point = new GeoPoint({
             lat: 31.230416,
@@ -2433,7 +2434,7 @@ describe('mongodb connector', function() {
     });
 
     it('create should convert geopoint to geojson', function(done) {
-      var point = new GeoPoint({lat: 1.243, lng: 20.4});
+      const point = new GeoPoint({lat: 1.243, lng: 20.4});
 
       PostWithLocation.create({location: point}, function(err, post) {
         should.not.exist(err);
@@ -2445,11 +2446,11 @@ describe('mongodb connector', function() {
     });
 
     it('find should be able to query by location', function(done) {
-      var coords = {lat: 1.25, lng: 20.2};
+      const coords = {lat: 1.25, lng: 20.2};
 
       geoDb.autoupdate(function(err) {
-        var createPost = function(callback) {
-          var point = new GeoPoint({
+        const createPost = function(callback) {
+          const point = new GeoPoint({
             lat: Math.random() * 180 - 90,
             lng: Math.random() * 360 - 180,
           });
@@ -2479,9 +2480,9 @@ describe('mongodb connector', function() {
                 should.not.exist(err);
                 should.exist(results);
 
-                var dist = 0;
+                let dist = 0;
                 results.forEach(function(result) {
-                  var currentDist = testUtils.getDistanceBetweenPoints(
+                  const currentDist = testUtils.getDistanceBetweenPoints(
                     coords,
                     result.location
                   );
@@ -2498,11 +2499,11 @@ describe('mongodb connector', function() {
     });
 
     it('find should be queryable using locations with deep/multiple keys', function(done) {
-      var coords = {lat: 1.25, lng: 20.2};
+      const coords = {lat: 1.25, lng: 20.2};
 
       geoDb.autoupdate(function(err) {
-        var heroNumber = 0;
-        var powers = ['fly', 'lasers', 'strength', 'drink'];
+        let heroNumber = 0;
+        const powers = ['fly', 'lasers', 'strength', 'drink'];
 
         function createSuperheroWithLocation(callback) {
           heroNumber++;
@@ -2553,9 +2554,9 @@ describe('mongodb connector', function() {
 
                 results.should.have.length(1);
 
-                var dist = 0;
+                let dist = 0;
                 results.forEach(function(result) {
-                  var currentDist = testUtils.getDistanceBetweenPoints(coords, {
+                  const currentDist = testUtils.getDistanceBetweenPoints(coords, {
                     lng: result.location.geometry.coordinates[0],
                     lat: result.location.geometry.coordinates[1],
                   });
@@ -2572,7 +2573,7 @@ describe('mongodb connector', function() {
     });
 
     it('find should be able to query by location via near with maxDistance', function(done) {
-      var coords = {lat: 30.274085, lng: 120.15507000000002};
+      const coords = {lat: 30.274085, lng: 120.15507000000002};
 
       geoDb.autoupdate(function(err) {
         async.parallel(
@@ -2597,9 +2598,9 @@ describe('mongodb connector', function() {
               function(err, results) {
                 if (err) return done(err);
                 results.length.should.be.equal(3);
-                var dist = 0;
+                let dist = 0;
                 results.forEach(function(result) {
-                  var currentDist = testUtils.getDistanceBetweenPoints(
+                  const currentDist = testUtils.getDistanceBetweenPoints(
                     coords,
                     result.location
                   );
@@ -2616,7 +2617,7 @@ describe('mongodb connector', function() {
     });
 
     it('find should be able to query by location via near with minDistance set', function(done) {
-      var coords = {lat: 30.274085, lng: 120.15507000000002};
+      const coords = {lat: 30.274085, lng: 120.15507000000002};
       geoDb.autoupdate(function(err) {
         async.parallel(
           [
@@ -2640,9 +2641,9 @@ describe('mongodb connector', function() {
               function(err, results) {
                 if (err) return done(err);
                 results.length.should.be.equal(1);
-                var dist = 0;
+                let dist = 0;
                 results.forEach(function(result) {
-                  var currentDist = testUtils.getDistanceBetweenPoints(
+                  const currentDist = testUtils.getDistanceBetweenPoints(
                     coords,
                     result.location
                   );
@@ -2658,10 +2659,10 @@ describe('mongodb connector', function() {
     });
 
     it('find should be able to set unit when query location via near', function(done) {
-      var coords = {lat: 30.274085, lng: 120.15507000000002};
+      const coords = {lat: 30.274085, lng: 120.15507000000002};
 
       geoDb.autoupdate(function(err) {
-        var queryLocation = function(
+        const queryLocation = function(
           distance,
           unit,
           distanceInMeter,
@@ -2682,7 +2683,7 @@ describe('mongodb connector', function() {
                 if (err) return done(err);
                 results.length.should.be.equal(numOfResult);
                 results.forEach(function(result) {
-                  var currentDist = testUtils.getDistanceBetweenPoints(
+                  const currentDist = testUtils.getDistanceBetweenPoints(
                     coords,
                     result.location
                   );
@@ -3131,31 +3132,31 @@ describe('mongodb connector', function() {
   });
 
   it('should export the MongoDB function', function() {
-    var module = require('../');
+    const module = require('../');
     module.MongoDB.should.be.an.instanceOf(Function);
   });
 
   it('should export the ObjectID function', function() {
-    var module = require('../');
+    const module = require('../');
     module.ObjectID.should.be.an.instanceOf(Function);
   });
 
   it('should export the generateMongoDBURL function', function() {
-    var module = require('../');
+    const module = require('../');
     module.generateMongoDBURL.should.be.an.instanceOf(Function);
   });
 
   describe('Test generateMongoDBURL function', function() {
-    var module = require('../');
+    const module = require('../');
     context('should return correct mongodb url ', function() {
       it('when only passing in database', function() {
-        var options = {
+        const options = {
           database: 'fakeDatabase',
         };
         module.generateMongoDBURL(options).should.be.eql('mongodb://127.0.0.1:27017/fakeDatabase');
       });
       it('when protocol is mongodb and no username/password', function() {
-        var options = {
+        const options = {
           protocol: 'mongodb',
           hostname: 'fakeHostname',
           port: 9999,
@@ -3164,7 +3165,7 @@ describe('mongodb connector', function() {
         module.generateMongoDBURL(options).should.be.eql('mongodb://fakeHostname:9999/fakeDatabase');
       });
       it('when protocol is mongodb and has username/password', function() {
-        var options = {
+        const options = {
           protocol: 'mongodb',
           hostname: 'fakeHostname',
           port: 9999,
@@ -3175,7 +3176,7 @@ describe('mongodb connector', function() {
         module.generateMongoDBURL(options).should.be.eql('mongodb://fakeUsername:fakePassword@fakeHostname:9999/fakeDatabase');
       });
       it('when protocol is mongodb+srv and no username/password', function() {
-        var options = {
+        const options = {
           protocol: 'mongodb+srv',
           hostname: 'fakeHostname',
           port: 9999,
@@ -3185,7 +3186,7 @@ describe('mongodb connector', function() {
         module.generateMongoDBURL(options).should.be.eql('mongodb+srv://fakeHostname/fakeDatabase');
       });
       it('when protocol is mongodb+srv and has username/password', function() {
-        var options = {
+        const options = {
           protocol: 'mongodb+srv',
           hostname: 'fakeHostname',
           port: 9999,
@@ -3200,7 +3201,7 @@ describe('mongodb connector', function() {
   });
 
   context('fieldsArrayToObj', function() {
-    var fieldsArrayToObj = require('../').fieldsArrayToObj;
+    const fieldsArrayToObj = require('../').fieldsArrayToObj;
     it('should export the fieldsArrayToObj function', function() {
       fieldsArrayToObj.should.be.an.instanceOf(Function);
     });
diff --git a/test/objectid.test.js b/test/objectid.test.js
index 67807a3fd..5d31a1258 100644
--- a/test/objectid.test.js
+++ b/test/objectid.test.js
@@ -7,7 +7,7 @@
 
 require('./init.js');
 
-var ds, Book, Chapter;
+let ds, Book, Chapter;
 
 describe('ObjectID', function() {
   before(function() {
@@ -32,26 +32,26 @@ describe('ObjectID', function() {
   });
 
   it('should convert 24 byte hex string as ObjectID', function() {
-    var ObjectID = ds.connector.getDefaultIdType();
-    var str = '52fcef5c0325ace8dcb7a0bd';
+    const ObjectID = ds.connector.getDefaultIdType();
+    const str = '52fcef5c0325ace8dcb7a0bd';
     ObjectID(str).should.be.an.instanceOf(ds.ObjectID);
   });
 
   it('should not convert 12 byte string as ObjectID', function() {
-    var ObjectID = ds.connector.getDefaultIdType();
-    var str = 'line-by-line';
+    const ObjectID = ds.connector.getDefaultIdType();
+    const str = 'line-by-line';
     ObjectID(str).should.be.equal(str);
   });
 
   it('should keep mongodb ObjectID as is', function() {
-    var ObjectID = ds.connector.getDefaultIdType();
-    var id = new ds.ObjectID();
+    const ObjectID = ds.connector.getDefaultIdType();
+    const id = new ds.ObjectID();
     ObjectID(id).should.be.an.instanceOf(ds.ObjectID);
   });
 
   it('should keep non-string id as it', function() {
-    var ObjectID = ds.connector.getDefaultIdType();
-    var id = 123;
+    const ObjectID = ds.connector.getDefaultIdType();
+    const id = 123;
     ObjectID(id).should.be.equal(123);
   });