finalized the code

Author: fayyazarshad

packages/optimizely-sdk/karma.base.conf.js

@@ -20,7 +20,7 @@ module.exports = {
   basePath: '',
 
   //plugins
-  plugins: ['karma-mocha', 'karma-webpack', require('karma-browserstack-launcher')],
+  plugins: ['karma-mocha', 'karma-webpack', require('karma-browserstack-launcher'), require('karma-babel-preprocessor')],
 
   webpack: {
     mode: 'production',
@@ -102,6 +102,12 @@ module.exports = {
     './lib/**/*tests.js': ['webpack'],
   },
 
+  babelPreprocessor: {
+     options: {
+       presets: ['@babel/preset-env'],
+     },
+  },
+
   // test results reporter to use
   // possible values: 'dots', 'progress'
   // available reporters: https://npmjs.org/browse/keyword/karma-reporter

packages/optimizely-sdk/lib/index.browser.js

@@ -25,22 +25,22 @@ import defaultErrorHandler from './plugins/error_handler';
 import defaultEventDispatcher from './plugins/event_dispatcher/index.browser';
 import eventProcessorConfigValidator from './utils/event_processor_config_validator';
 
-var logger = sdkLogging.getLogger();
+const logger = sdkLogging.getLogger();
 sdkLogging.setLogHandler(loggerPlugin.createLogger());
 sdkLogging.setLogLevel(sdkLogging.LogLevel.INFO);
 
-var MODULE_NAME = 'INDEX_BROWSER';
-var DEFAULT_EVENT_BATCH_SIZE = 10;
-var DEFAULT_EVENT_FLUSH_INTERVAL = 1000; // Unit is ms, default is 1s
+const MODULE_NAME = 'INDEX_BROWSER';
+const DEFAULT_EVENT_BATCH_SIZE = 10;
+const DEFAULT_EVENT_FLUSH_INTERVAL = 1000; // Unit is ms, default is 1s
 
 var hasRetriedEvents = false;
 
-export var logging = loggerPlugin;
-export var errorHandler = defaultErrorHandler;
-export var eventDispatcher = defaultEventDispatcher;
-export var enums = utilEnums;
-export var setLogger = sdkLogging.setLogHandler;
-export var setLogLevel = sdkLogging.setLogLevel;
+export const logging = loggerPlugin;
+export const errorHandler = defaultErrorHandler;
+export const eventDispatcher = defaultEventDispatcher;
+export const enums = utilEnums;
+export const setLogger = sdkLogging.setLogHandler;
+export const setLogLevel = sdkLogging.setLogLevel;
 
 /**
  * Creates an instance of the Optimizely class
@@ -55,7 +55,7 @@ export var setLogLevel = sdkLogging.setLogLevel;
  * @param {Object} config.eventFlushInterval
  * @return {Object} the Optimizely object
  */
-export var createInstance = function(config) {
+export const createInstance = function(config) {
   try {
     config = config || {};
 
@@ -86,7 +86,7 @@ export var createInstance = function(config) {
       config.skipJSONValidation = true;
     }
 
-    var eventDispatcher;
+    let eventDispatcher;
     // prettier-ignore
     if (config.eventDispatcher == null) { // eslint-disable-line eqeqeq
       // only wrap the event dispatcher with pending events retry if the user didnt override
@@ -130,11 +130,11 @@ export var createInstance = function(config) {
       config.eventFlushInterval = DEFAULT_EVENT_FLUSH_INTERVAL;
     }
 
-    var optimizely = new Optimizely(config);
+    const optimizely = new Optimizely(config);
 
     try {
       if (typeof window.addEventListener === 'function') {
-        var unloadEvent = 'onpagehide' in window ? 'pagehide' : 'unload';
+        const unloadEvent = 'onpagehide' in window ? 'pagehide' : 'unload';
         window.addEventListener(
           unloadEvent,
           function() {
@@ -154,7 +154,7 @@ export var createInstance = function(config) {
   }
 };
 
-export var __internalResetRetryState = function() {
+export const __internalResetRetryState = function() {
   hasRetriedEvents = false;
 };