fix(project config manager): Don't log an error when not initialized with datafile (#589)

Summary:

Fixes a regression introduced during refactoring for datafile accessor - any time the datafile property of the object passed to createInstance is missing or falsy, the logger will output (for example):

[OPTIMIZELY] - ERROR 2020-10-05T23:38:15.224Z CONFIG_VALIDATOR: No datafile specified. Cannot start optimizely

Passing in an sdkKey, but no datafile, is valid and supported when calling createInstance, but this message leads the user to believe otherwise. In this situation, nothing is actually wrong, but the message says "Cannot start optimizely".

To fix, in ProjectConfigManager __initialize, when config.datafile is falsy, we do not call __handleNewDatafile, avoiding the code path that eventually would log the error message.

Test plan:

- Added new unit test
- Manually tested

Author: mjc1283

packages/optimizely-sdk/CHANGELOG.MD

@@ -10,6 +10,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 ### Bug fixes
 
 - Fixed return type of `getAllFeatureVariables` method and `dispatchEvent ` method signature of `EventDispatcher` interface in TypeScript type definitions ([#576](https://github.com/optimizely/javascript-sdk/pull/576))
+- Don't log an error message when initialized with `sdkKey`, but no `datafile` ([#589](https://github.com/optimizely/javascript-sdk/pull/589))
 
 ## [4.3.1] - October 5, 2020
 

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

@@ -91,8 +91,13 @@ ProjectConfigManager.prototype.__initialize = function(config) {
     return;
   }
 
-  var handleNewDatafileException = this.__handleNewDatafile(config.datafile);
-  if (handleNewDatafileException) {
+  let handleNewDatafileException;
+  if (config.datafile) {
+    handleNewDatafileException = this.__handleNewDatafile(config.datafile);
+    if (handleNewDatafileException) {
+      this.__configObj = null;
+    }
+  } else {
     this.__configObj = null;
   }
 

packages/optimizely-sdk/lib/core/project_config/project_config_manager.tests.js

@@ -347,6 +347,13 @@ describe('lib/core/project_config/project_config_manager', function() {
         manager.stop();
         sinon.assert.calledOnce(datafileManager.HttpPollingDatafileManager.getCall(0).returnValue.stop);
       });
+
+      it('does not log an error message', function() {
+        projectConfigManager.createProjectConfigManager({
+          sdkKey: '12345',
+        });
+        sinon.assert.notCalled(stubLogHandler.log);
+      });
     });
 
     describe('when constructed with sdkKey and with a valid datafile object', function() {