fix: Use default event dispatcher in React Native entry point when none provided by user (#383)

Summary:

In the createInstance factory method of the React Native entry point, when no event dispatcher is provided by the caller in the options object, a value of undefined is set on the options object that is passed on to the Optimizely constructor. This results in an invalid instance that can't dispatch events.

With this fix, the default event dispatcher is used when none is provided by the caller.

Test plan:

Added new unit test

Author: mjc1283

packages/optimizely-sdk/CHANGELOG.MD

@@ -5,7 +5,8 @@ The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/)
 and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.html).
 
 ## [Unreleased]
-Changes that have landed but are not yet released.
+### Bug fixes
+- Fixed default event dispatcher not used in React Native entry point ([#383](https://github.com/optimizely/javascript-sdk/pull/383))
 
 ## [3.4.0-beta] - December 18th, 2019
 ### Bug fixes
@@ -14,7 +15,7 @@ Changes that have landed but are not yet released.
 ### New Features
 
 - Added a new API to get a project configuration static data.
-  - Call `getOptimizelyConfig()` to get a snapshot copy of project configuration static data. 
+  - Call `getOptimizelyConfig()` to get a snapshot copy of project configuration static data.
   - It returns an `OptimizelyConfig` instance which includes a datafile revision number, all experiments, and feature flags mapped by their key values.
   - For details, refer to a documention page: https://docs.developers.optimizely.com/full-stack/docs/optimizelyconfig-javascript-node
 

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

@@ -90,11 +90,11 @@ module.exports = {
         {
           clientEngine: enums.JAVASCRIPT_CLIENT_ENGINE,
           eventBatchSize: DEFAULT_EVENT_BATCH_SIZE,
+          eventDispatcher: defaultEventDispatcher,
           eventFlushInterval: DEFAULT_EVENT_FLUSH_INTERVAL,
         },
         config,
         {
-          eventDispatcher: config.eventDispatcher,
           // always get the OptimizelyLogger facade from logging
           logger: logger,
           errorHandler: logging.getErrorHandler(),

packages/optimizely-sdk/lib/index.react_native.tests.js

@@ -22,6 +22,7 @@ var packageJSON = require('../package.json');
 var testData = require('./tests/test_data');
 var eventProcessor = require('@optimizely/js-sdk-event-processor');
 var eventProcessorConfigValidator = require('./utils/event_processor_config_validator');
+var defaultEventDispatcher = require('./plugins/event_dispatcher/index.browser');
 
 var chai = require('chai');
 var assert = chai.assert;
@@ -131,6 +132,30 @@ describe('javascript-sdk/react-native', function() {
         assert.strictEqual(activate, 'control');
       });
 
+      describe('when no event dispatcher passed to createInstance', function() {
+        beforeEach(function() {
+          sinon.stub(defaultEventDispatcher, 'dispatchEvent', function(evt, cb) {
+            cb();
+          });
+        })
+
+        afterEach(function() {
+          defaultEventDispatcher.dispatchEvent.restore();
+        });
+
+        it('uses the default event dispatcher', function() {
+          var optlyInstance = optimizelyFactory.createInstance({
+            datafile: testData.getTestProjectConfig(),
+            errorHandler: fakeErrorHandler,
+            logger: silentLogger,
+          });
+          optlyInstance.activate('testExperiment', 'testUser');
+          return optlyInstance.close().then(function() {
+            sinon.assert.calledOnce(defaultEventDispatcher.dispatchEvent);
+          });
+        });
+      });
+
       describe('when passing in logLevel', function() {
         beforeEach(function() {
           sinon.stub(logging, 'setLogLevel');