refactor: Removed dependency on lodash.forEach (#412)

Summary:

to reduce package size, we are trying to gradually get rid of lodash library. This PR removes the implementation of fns.forEach and replaced it with default forEach method of arrays and Object.Keys for maps

Test plan:

All tests are passing

Co-authored-by: zashraf1985 <35262377+zashraf1985@users.noreply.github.com>

Author: fayyazarshad

packages/optimizely-sdk/lib/core/notification_center/index.js

@@ -66,7 +66,7 @@ NotificationCenter.prototype.addNotificationListener = function (notificationTyp
     }
 
     var callbackAlreadyAdded = false;
-    fns.forEach(this.__notificationListeners[notificationType], function (listenerEntry) {
+    (this.__notificationListeners[notificationType] || []).forEach(function(listenerEntry) {
       if (listenerEntry.callback === callback) {
         callbackAlreadyAdded = true;
         return false;
@@ -102,12 +102,13 @@ NotificationCenter.prototype.removeNotificationListener = function (listenerId)
     var indexToRemove;
     var typeToRemove;
     fns.forOwn(this.__notificationListeners, function (listenersForType, notificationType) {
-      fns.forEach(listenersForType, function (listenerEntry, i) {
+      (listenersForType || []).every(function(listenerEntry, i) {
         if (listenerEntry.id === listenerId) {
           indexToRemove = i;
           typeToRemove = notificationType;
           return false;
         }
+        return true
       });
       if (indexToRemove !== undefined && typeToRemove !== undefined) {
         return false;
@@ -160,7 +161,7 @@ NotificationCenter.prototype.clearNotificationListeners = function (notification
  */
 NotificationCenter.prototype.sendNotifications = function (notificationType, notificationData) {
   try {
-    fns.forEach(this.__notificationListeners[notificationType], function (listenerEntry) {
+    (this.__notificationListeners[notificationType] || []).forEach(function(listenerEntry) {
       var callback = listenerEntry.callback;
       try {
         callback(notificationData);

packages/optimizely-sdk/lib/core/project_config/index.js

@@ -41,7 +41,7 @@ module.exports = {
      * Conditions of audiences in projectConfig.typedAudiences are not
      * expected to be string-encoded as they are here in projectConfig.audiences.
      */
-    fns.forEach(projectConfig.audiences, function(audience) {
+    (projectConfig.audiences || []).forEach(function(audience) {
       audience.conditions = JSON.parse(audience.conditions);
     });
     projectConfig.audiencesById = fns.keyBy(projectConfig.audiences, 'id');
@@ -52,16 +52,16 @@ module.exports = {
     projectConfig.groupIdMap = fns.keyBy(projectConfig.groups, 'id');
 
     var experiments;
-    fns.forEach(projectConfig.groupIdMap, function(group, Id) {
-      experiments = fns.cloneDeep(group.experiments);
-      fns.forEach(experiments, function(experiment) {
+    Object.keys(projectConfig.groupIdMap || {}).forEach(function(Id) {
+      experiments = fns.cloneDeep(projectConfig.groupIdMap[Id].experiments);
+      (experiments || []).forEach(function(experiment) {
         projectConfig.experiments.push(fns.assign(experiment, {groupId: Id}));
       });
     });
 
     projectConfig.rolloutIdMap = fns.keyBy(projectConfig.rollouts || [], 'id');
     fns.forOwn(projectConfig.rolloutIdMap, function(rollout) {
-      fns.forEach(rollout.experiments || [], function(experiment) {
+      (rollout.experiments || []).forEach(function(experiment) {
         projectConfig.experiments.push(fns.cloneDeep(experiment));
         // Creates { <variationKey>: <variation> } map inside of the experiment
         experiment.variationKeyMap = fns.keyBy(experiment.variations, 'key');
@@ -73,7 +73,7 @@ module.exports = {
 
     projectConfig.variationIdMap = {};
     projectConfig.variationVariableUsageMap = {};
-    fns.forEach(projectConfig.experiments, function(experiment) {
+    (projectConfig.experiments || []).forEach(function(experiment) {
       // Creates { <variationKey>: <variation> } map inside of the experiment
       experiment.variationKeyMap = fns.keyBy(experiment.variations, 'key');
 
@@ -94,7 +94,7 @@ module.exports = {
     projectConfig.featureKeyMap = fns.keyBy(projectConfig.featureFlags || [], 'key');
     fns.forOwn(projectConfig.featureKeyMap, function(feature) {
       feature.variableKeyMap = fns.keyBy(feature.variables, 'key');
-      fns.forEach(feature.experimentIds || [], function(experimentId) {
+      (feature.experimentIds || []).forEach(function(experimentId) {
         // Add this experiment in experiment-feature map.
         if (projectConfig.experimentFeatureMap[experimentId]) {
           projectConfig.experimentFeatureMap[experimentId].push(feature.id);

packages/optimizely-sdk/lib/utils/fns/index.js

@@ -54,7 +54,6 @@ module.exports = {
       return item[key];
     });
   },
-  forEach: require('lodash/forEach'),
   forOwn: require('lodash/forOwn'),
   uuid: function() {
     return uuid.v4();