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Javascript method is not a constructor

at the company where Im at we use jquery and a lot of the code is very spaghetti haphazard code. So in an effort to organize it better im researching implementing the pub sub model described in this article
So I made a really basic version of it like so:
var topics = {};
jQuery.Topic = function( id ) {
var callbacks, method,
topic = id && topics[ id ];
if ( !topic ) {
callbacks = jQuery.Callbacks();
topic = {
publish: callbacks.fire,
subscribe: callbacks.add,
unsubscribe: callbacks.remove
};
if ( id ) {
topics[ id ] = topic;
}
}
return topic;
};
$(function() {
var testService = new TestService();
testService.subscribe();
var testView = new TestView(testService);
testView.initEvents();
});
/* ---------------------VIEW----------------- */
var TestView = function(testService) {
this.testService = testService;
};
TestView.prototype.initEvents = function () {
this.publishers();
};
TestView.prototype.publishers = function() {
$("#search").on("click", function () {
var isValid = this.testService.validateForm("#container");
if(isValid){
$.Topic( "search" ).publish();
}
})
};
/* ---------------------SERVICE----------------- */
var TestService = function() {
this.testIdea = [];
};
TestService.prototype.validateForm = function (section) {
var referralValid = true;
$(section).find('input,select').filter('[required]:visible').each(function (i, requiredField) {
if(requiredField.value === '') {
//'breaks' the loop out
referralValid = false;
return referralValid;
}
});
return referralValid;
};
TestService.prototype.search = function() {
};
TestService.prototype.subscribe = function() {
var self = this;
$.Topic("search").subscribe( function() {
self.search()
});
};
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.1/jquery.min.js"></script>
<div>
<div id="container">
<input type="text">
</div>
<button id="search">Search</button>
</div>
However when I put that in jsfiddle I get the error that Uncaught TypeError: TestService is not a constructor
in the stackoverflow snippet and on my local version I get a different error of Uncaught TypeError: Cannot read property 'validateForm' of undefined. I cant see what Im doing wrong. Any pointers?

You can declare constructor functions in the way you are doing it (assigning constructor to variable):
var TestView = function(testService) {
this.testService = testService;
};
Like in this simple example:
var myClass = function(name) {
this.name = name;
}
myClass.prototype = {
hello: function() {
console.log('Hello ' + this.name);
}
}
var me = new myClass('Andrew');
me.hello();
But you must remember to declare them before they are used. If you use function statement(https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/function) as suggested by Chad Watkins it helps only because of hoisting(http://adripofjavascript.com/blog/drips/variable-and-function-hoisting.html) not because of function statement being mandatory for constructors.
The error in your code is in line:
$("#search").on("click", function () {
var isValid = this.testService.validateForm("#container");
you are referencing jQuery object inside a callback not TestView instance, you probably wanted something like this(pun not intended):
...
var self = this;
$("#search").on("click", function () {
var isValid = self.testService.validateForm("#container");
...

Possible failed dependency injection using require throws 'is not a function' error

I've looked through a few questions related to this error, and most of them seem to be a misunderstanding of what the keyword this means. I don't think I'm having that problem here. Mine might be some sort of circular dependency problem that I cannot articulate well enough to figure it out on my own.
I've tried to distill my problem into three files presented below.
something.js
var A = require('../lib/a');
var Something = function (type) {
this.type = type;
};
Something.prototype.setTemplate = function (template) {
this.template = template;
};
Something.prototype.applyTemplate = function () {
var templateResult = this.template.calculate();
};
var factory = {};
factory.createSomething = function(type) {
return new Something(type);
};
factory.createA = function (input) {
return A.Make(input);
};
module.exports = factory;
a.js
var S = require('../prof/something');
var _ = require('underscore');
var A = function (input) {
this.input = input;
};
A.prototype.calculate = function () {
var calculation = 0;
var _s = S.createSomething('hello world');
// do calculation using input
return calculation;
};
var factory = {};
factory.Make = function (input) {
var a = new A(input);
return a;
};
module.exports = factory;
a_test.js
describe('Unit: A Test', function() {
var S = require('../prof/something');
it('test 1', function() {
var a = S.createA({
//input
});
var s = S.createSomething('type1');
s.setTemplate(a);
s.applyTemplate(); // error
});
});
The error gets thrown from the top level in a_test.js on the line with the comment //error. At the lowest level, the 'is not a function ' error is thrown in a.js at the S.createSomething(type) method. It says that S.createSomething() is not a function.
I've put a breakpoint in at that line and tried to call functions from the underscore library, but it gives the same error. So it seems that the require statements inside a.js are not throwing errors, but none of the injected objects can be used to call functions from. The a_test.js file is being run with the karma library.
Am I violating some javascript paradigm by referencing back and forth between A and S? How can I do this properly?
Edit: I've done some further testing. It doesn't actually matter if the test file looks like this:
describe('Unit: A Test', function() {
var S = require('../prof/something');
it('test 1', function() {
var a = S.createA({
//input
});
a.calculate(); // error
});
});
An error is still thrown at the line indicated above.

The files in the question reference each other. This is called cyclic dependencies. The solution is to move the var S = require('../prof/something'); statement into the calculate function like so:
a.js
// move the line from here
var _ = require('underscore');
var A = function (input) {
this.input = input;
};
A.prototype.calculate = function () {
var S = require('../prof/something'); // to here
var calculation = 0;
var _s = S.createSomething('hello world');
// do calculation using input
return calculation;
};
var factory = {};
factory.Make = function (input) {
var a = new A(input);
return a;
};
module.exports = factory;

Sinon stub not working when trying to mock out an instance of an object

I am trying to mock out every instance that is created with the new keyword for an object.
Here is the Object I am trying to mock out:
var SharedWhiteboardView = function(moduleEl, domService) {
'use strict';
var self;
var sharedWhiteboardProblemImage;
var whiteboardController;
var caller = false;
var toolbarController;
return {
initWhiteboard : function()
{
self = this;
sharedWhiteboardProblemImage = domService.find(moduleEl, '#sharedWhiteboardModule-sharedWhiteboardProblemImage');
var toolbarEL = $('#sharedWhiteboard-toolbar');
toolbarController = new ToolbarController(WhiteboardConstants.SHARED_WHITEBOARD_ID, toolbarEL, null);
toolbarController.init(false);
whiteboardController = toolbarController.getWhiteboardController();
},
enableWhiteboardEdition : function(enabled)
{
if(self.getWhiteboardObject() && self.getWhiteboardObject.hasOwnProperty('enableEdition')) self.getWhiteboardObject().enableEdition(enabled);
whiteboardController.setEnabled(enabled);
}
};
}
This is the file which I am trying to test and it creates a new instance of the above object
Box.Application.addModule('SharedWhiteboardModule', function(context) {
'use strict';
var self;
var moduleEl;
var domService;
var sharedWhiteboardView;
var modal;
var assignmentTimer = 3000;
var sharing = false;
var assignmentImageData = '';
return {
/**
* Initializes the module and caches the module element
* #returns {void}
*/
init: function() {
self = this;
domService = context.getService('DomService');
moduleEl = context.getElement();
sharedWhiteboardView = new SharedWhiteboardView(moduleEl, domService);
sharedWhiteboardView.initWhiteboard();
sharedWhiteboardView.enableWhiteboardEdition(false);
};
}
I am trying to write a unit test to test that the sharedWhiteboardView.enableWhiteboardEdition method is called with 'false'
However I am failing to attach a spy or stub that method out. I have tried these solutions and they did not work
//First Attempt
sinon.stub(SharedWhiteboardView, "enableWhiteboardEdition", function() {return 0})
// Second Attempt
sinon.stub(SharedWhiteboardView.prototype, "enableWhiteboardEdition").returns(0);
//Third Attempt
sandbox.stub(SharedWhiteboardView.prototype, 'enableWhiteboardEdition', checkEnableWhiteboardEdition());
//Fourth Attempt Trying the answer provided by chrmod
it.only('when type is "SharedWhiteboardModule-setEditable" should call sharedWhiteboardView.enableWhiteboardEdition', function (done) {
const view = SharedWhiteboardView();
sinon.stub(view, "enableWhiteboardEdition", function() {
console.log('Hit');
});
module.onmessage('SharedWhiteboardModule-setEditable', true);
done();
});
No error but it does not hit the console.log, I removed the 'new' keyword as suggested
Errors that I got:
-Attempted to wrap undefined property enableWhiteboardEdition as function
-Cannot stub non-existent own property enableWhiteboardEdition
Please any help would be great. I have reached a dead end here.
Here is a codepen: http://codepen.io/anon/pen/bgmNxx?editors=0011
All I am trying to do is to have the Fake method get hit when my module calls enableEdition

SharedWhiteboardView is not a constructor, it is rather a factory function. Once called (without new) it returns new object that has enableWhiteboardEdition as own property.
Thus a stub has to be set on that object:
const view = SharedWhiteboardView();
sinon.stub(view, "enableWhiteboardEdition", function() {return 0});

This did it.
it('when type is "SharedWhiteboardModule-setEditable" should call setEditable with appropriate callback', function (done) {
var mockSharedWhiteboardView = {
enableWhiteboardEdition: function() {},
initWhiteboard: function() {},
initScrollBar: function() {},
refreshScrollBar: function() {},
isMainWhiteboardAvailable: function() {}
};
sandbox.spy(mockSharedWhiteboardView, 'enableWhiteboardEdition');
var tempGlobals = {
SharedWhiteboardView: global.SharedWhiteboardView
};
global.SharedWhiteboardView = function() {
return mockSharedWhiteboardView;
};
module = Box.Application.getModuleForTest('SharedWhiteboardModule', contextFake);
module.init();
var shouldEnable = true;
module.onmessage('SharedWhiteboardModule-setEditable', shouldEnable);
assert(mockSharedWhiteboardView.enableWhiteboardEdition.calledWithExactly(shouldEnable),
'should enable the whiteboard');
shouldEnable = false;
module.onmessage('SharedWhiteboardModule-setEditable', shouldEnable);
assert(mockSharedWhiteboardView.enableWhiteboardEdition.calledWithExactly(shouldEnable),
'should not enable the whiteboard');
// cleanup
global.SharedWhiteboardView = tempGlobals.SharedWhiteboardView;
done();
});

How do I stub/mock a dependency's method copied from "superclass" with sinon

I'm having problems testing a Store in flux, wanting to stub out the dispatcher. I've seen how it's done with jest, but I Want to achieve the same with sinon.
Here's what I have
Source
lib/Dispatcher. Full code here
var invariant = require('./invariant');
//...
function Dispatcher() {
this.$Dispatcher_callbacks = {};
}
Dispatcher.prototype.register=function(callback) {
var id = _prefix + _lastID++;
this.$Dispatcher_callbacks[id] = callback;
return id;
};
// ...
module.exports = Dispatcher;
Dispatcher:
module.exports.Dispatcher = require('./lib/Dispatcher')
AppDispatcher:
var Dispatcher = require('flux').Dispatcher;
var copyProperties = require('react/lib/copyProperties');
var AppDispatcher = copyProperties(new Dispatcher(), {
handleViewAction: function(action) {
this.dispatch({
source: 'VIEW_ACTION',
action: action
});
}
});
module.exports = AppDispatcher;
ItemStore, the one I want to test
var AppDispatcher = require('../dispatcher/AppDispatcher');
var EventEmitter = require('events').EventEmitter;
var ItemConstants = require('../constants/ItemConstants');
var merge = require('react/lib/merge');
var CHANGE_EVENT = 'change';
var _items = [];
var ItemStore = merge(EventEmitter.prototype, {
getSoekeresultat: function() {
return _items;
},
emitChange: function() {
this.emit(CHANGE_EVENT);
}
});
AppDispatcher.register(function(payload) {
var action = payload.action;
switch(action.actionType) {
case ItemConstants.ITEMS_FETCHED:
_items = action.payload;
ItemStore.emitChange();
break;
default:
}
return true; // No errors. Needed by promise in Dispatcher.
});
module.exports = ItemStore;
So what I want to stub is AppDispatcher.register. How do I do that?
I've tried doing it several ways, the last I tried was this:
var sinon = require("sinon");
require("jasmine-sinon");
describe("ItemStore", function(){
var AppDispatcher = require('js/dispatcher/AppDispatcher.js');
sinon.stub(AppDispatcher, 'register', function () {
console.log("stub");
});
it("should use stub when called directly", function(){
AppDispatcher.register(function (payload) {
});
//outputs "stub"
});
it("should use stub when requiring itemstore", function(){
var ItemStore = require('js/stores/ItemStore.js');
// doesn't output "stub"
});
});
Can someone tell me how to stub it?

Although it's not strictly answering your question, you can achieve what you're trying to using proxyquire. It'll allow you to stub the AppDispatcher that is required inside ItemStore. e.g.
var proxyquire = require('proxyquire');
var AppDispatcher = require('js/dispatcher/AppDispatcher.js');
var StubbedAppDispatcher = sinon.stub(AppDispatcher)
/*
* This will load the `ItemStore` module, satisfying it's `AppDispatcher`
* dependency (the `require('../dispatcher/AppDispatcher')` statement)
* with our stubbed version.
*/
var ItemStore = proxyquire('js/stores/ItemStore.js', {
'../dispatcher/AppDispatcher': StubbedAppDispatcher
});

Overiding a prototype method

I have a javascript base function like this;
roomBase = function () {
this.go = function(){
alert(1);
}
}
I have a room object like this;
myRoom = function(){
this.go = function(){
alert(456);
}
}
myRoom.prototype = new roomBase();
theRoom = new myRoom();
When I call theRoom.go() I am getting an alert from the prototype. What I want is the alert from the myRoom function instead.

It works fine for me. (it alerts 456)
Are you sure everything is running correctly?
Demo: http://jsfiddle.net/9hWAr/
Code for Demo:
var roomBase = function () {
this.go = function(){
alert(1);
}
}
var myRoom = function(){
this.go = function(){
alert(456);
}
}
myRoom.prototype = new roomBase();
var theRoom = new myRoom();
theRoom.go()