Update todomvc dispatcher to match docs, add AppDispatcher test

Author: joshma

examples/todomvc-flux/js/dispatcher/Dispatcher.js

@@ -27,28 +27,6 @@ var merge = require('react/lib/merge');
 var _callbacks = [];
 var _promises = [];
 
-/**
- * Add a promise to the queue of callback invocation promises.
- * @param {function} callback The Store's registered callback.
- * @param {object} payload The data from the Action.
- */
-var _addPromise = function(callback, payload) {
- _promises.push(new Promise(function(resolve, reject) {
- if (callback(payload)) {
- resolve(payload);
- } else {
- reject(new Error('Dispatcher callback unsuccessful'));
- }
- }));
-};
-
-/**
- * Empty the queue of callback invocation promises.
- */
-var _clearPromises = function() {
- _promises = [];
-};
-
 var Dispatcher = function() {};
 Dispatcher.prototype = merge(Dispatcher.prototype, {
 
@@ -67,10 +45,26 @@ Dispatcher.prototype = merge(Dispatcher.prototype, {
  * @param {object} payload The data from the action.
  */
  dispatch: function(payload) {
- _callbacks.forEach(function(callback) {
- _addPromise(callback, payload);
+ // First create array of promises for callbacks to reference.
+ var _resolves = [];
+ var _rejects = [];
+ _promises = _callbacks.map(function(_, i) {
+ return new Promise(function(resolve, reject) {
+ _resolves[i] = resolve;
+ _rejects[i] = reject;
+ });
+ });
+ // Dispatch to callbacks and resolve/reject promises.
+ _callbacks.forEach(function(callback, i) {
+ // Callback can return an obj, to resolve, or a promise, to chain.
+ // See waitFor() for why this might be useful.
+ Promise.resolve(callback(payload)).then(function() {
+ _resolves[i](payload);
+ }, function() {
+ _rejects[i](new Error('Dispatcher callback unsuccessful'));
+ });
  });
- Promise.all(_promises).then(_clearPromises);
+ _promises = [];
  },
 
  /**
@@ -108,10 +102,10 @@ Dispatcher.prototype = merge(Dispatcher.prototype, {
  * A more robust Dispatcher would issue a warning in this scenario.
  */
  waitFor: function(/*array*/ promiseIndexes, /*function*/ callback) {
- var selectedPromises = _promises.filter(function(/*object*/ _, /*number*/ j) {
- return promiseIndexes.indexOf(j) !== -1;
+ var selectedPromises = promiseIndexes.map(function(index) {
+ return _promises[index];
  });
- Promise.all(selectedPromises).then(callback);
+ return Promise.all(selectedPromises).then(callback);
  }
 
 });

examples/todomvc-flux/js/dispatcher/__tests__/AppDispatcher-test.js

@@ -0,0 +1,66 @@
+"use strict";
+
+jest.autoMockOff();
+
+describe('AppDispatcher', function() {
+ var AppDispatcher;
+
+ beforeEach(function() {
+ AppDispatcher = require('../AppDispatcher.js');
+ });
+
+ it('sends actions to subscribers', function() {
+ var listener = jest.genMockFunction();
+ AppDispatcher.register(listener);
+
+ var payload = {};
+ AppDispatcher.dispatch(payload);
+ expect(listener.mock.calls.length).toBe(1);
+ expect(listener.mock.calls[0][0]).toBe(payload);
+ });
+
+ it.only('waits with chained dependencies properly', function() {
+ var payload = {};
+
+ var listener1Done = false;
+ var listener1 = function(pl) {
+ return AppDispatcher.waitFor([index2], function() {
+ // Second and third listeners should have now been called
+ expect(listener2Done).toBe(true);
+ expect(listener3Done).toBe(true);
+ listener1Done = true;
+ });
+ };
+ var index1 = AppDispatcher.register(listener1);
+
+ var listener2Done = false;
+ var listener2 = function(pl) {
+ return AppDispatcher.waitFor([index3], function() {
+ expect(listener3Done).toBe(true);
+ listener2Done = true;
+ });
+ };
+ var index2 = AppDispatcher.register(listener2);
+
+ var listener3Done = false;
+ var listener3 = function(pl) {
+ listener3Done = true;
+ return true;
+ };
+ var index3 = AppDispatcher.register(listener3);
+
+ runs(function() {
+ AppDispatcher.dispatch(payload);
+ });
+
+ waitsFor(function() {
+ return listener1Done;
+ }, "Not all subscribers were properly called", 500);
+
+ runs(function() {
+ expect(listener1Done).toBe(true);
+ expect(listener2Done).toBe(true);
+ expect(listener3Done).toBe(true);
+ });
+ });
+});

examples/todomvc-flux/package.json

@@ -13,7 +13,8 @@
  "reactify": "~0.4.0",
  "statics": "~0.1.0",
  "uglify-js": "~2.4.13",
- "watchify": "~0.4.1"
+ "watchify": "~0.4.1",
+ "jest-cli": "~0.1.5"
  },
  "scripts": {
  "start": "STATIC_ROOT=./static watchify -o js/bundle.js -v -d .",