Fixed error in _getCallableModule method in MessageQueue

Reviewed By: javache

Differential Revision: D5208462

fbshipit-source-id: 13f71e2b7988305eccfa91c349ff120fad9129f0

Libraries/BatchedBridge/MessageQueue.js

@@ -152,7 +152,8 @@ class MessageQueue {
  }
 
  _getCallableModule(name: string) {
- return this._lazyCallableModules[name]();
+ const getValue = this._lazyCallableModules[name];
+ return getValue ? getValue() : null;
  }
 
  enqueueNativeCall(moduleID: number, methodID: number, params: Array<any>, onFail: ?Function, onSucc: ?Function) {

Libraries/BatchedBridge/__tests__/MessageQueue-test.js

@@ -83,4 +83,33 @@ describe('MessageQueue', function() {
  queue.__invokeCallback(1);
  expect(() => queue.__invokeCallback(0)).toThrow();
  });
+
+ it('should throw when calling with unknown module', () => {
+ const unknownModule = 'UnknownModule', unknownMethod = 'UnknownMethod';
+ expect(() => queue.__callFunction(unknownModule, unknownMethod)).toThrow(
+ `Module ${unknownModule} is not a registered callable module (calling ${unknownMethod})`,
+ );
+ });
+
+ it('should return lazily registered module', () => {
+ const dummyModule = {}, name = 'modulesName';
+ queue.registerLazyCallableModule(name, () => dummyModule);
+ expect(queue._getCallableModule(name)).toEqual(dummyModule);
+ });
+
+ it('should not initialize lazily registered module before it was used for the first time', () => {
+ const dummyModule = {}, name = 'modulesName';
+ const factory = jest.fn(() => dummyModule);
+ queue.registerLazyCallableModule(name, factory);
+ expect(factory).not.toHaveBeenCalled();
+ });
+
+ it('should initialize lazily registered module only once', () => {
+ const dummyModule = {}, name = 'modulesName';
+ const factory = jest.fn(() => dummyModule);
+ queue.registerLazyCallableModule(name, factory);
+ queue._getCallableModule(name);
+ queue._getCallableModule(name);
+ expect(factory).toHaveBeenCalledTimes(1);
+ });
 });