Backbone.js:"Maximum call stack size exceeded" error - backbone.js

suppose I have a model and a view ,ths view have two method:one is bind the document mousemove event and the other is unbind method,defalut I give the document mousemove event, once the model's enable value changed I will call the view's unbind method:
window.ConfigModel = Backbone.Model.extend({
defaults: {
'enable':0
},
initialize: function(){
this.bind("change:enable", function () {
var portView2 = new PortView();
portView2.viewOff();
});
},
change:function () {
this.set('enable', 9);
}
})
window.PortView = Backbone.View.extend({
viewOn: function () {
$(document).on('mousemove', function () {
console.log('move')
})
},
viewOff: function () {
$(document).off('mousemove');
}
})
then I put an input on the document to call the model changed:
$('input').click(function () {
var configModel = new ConfigModel();
configModel.change();
})
the boot script is :
var portView1 = new PortView();
portView1.viewOn();
The problem is once I call the click the input button ,the chrome would tell me an error:Maximum call stack size exceeded it seems the change be invoke many times.So what's the problem with my problem ,how can I solve this problem

Backbone models already have a change method:
change model.change()
Manually trigger the "change" event and a "change:attribute" event for each attribute that has changed. If you've been passing {silent: true} to the set function in order to aggregate rapid changes to a model, you'll want to call model.change() when you're all finished.
Presumably something inside Backbone is trying to call configModel.change() and getting your version of change which triggers another change() call inside Backbone which runs your change which ... until the stack blows up.
You should use a different name for your change method.
That said, your code structure is somewhat bizarre. A model listening to events on itself is well and good but a model creating a view is odd:
initialize: function() {
this.bind("change:enable", function () {
var portView2 = new PortView();
portView2.viewOff();
});
}
And instantiating a view simply to call a single method and then throw it away is strange as is creating a new model just to trigger an event.
I think you probably want to have a single ConfigModel instance as part of your application state, say app.config. Then your click handler would talk to that model:
$('input').click(function () {
app.config.enable_level_9(); // or whatever your 'change' gets renamed to
});
Then you'd have some other part of your application (not necessarily a view) that listens for changes to app.config and acts appropriately:
app.viewOn = function() {
$(document).on('mousemove', function() {
console.log('move')
});
};
app.viewOff = function() {
$(document).off('mousemove');
};
app.init = function() {
app.config = new ConfigModel();
app.viewOn();
$('input').click(function () {
app.config.enable_level_9();
});
// ...
};
And then start the application with a single app.init() call:
$(function() {
app.init();
});

Related

Backbone trigger event after custom function possible?

Excuse my backbone i'm not an expert, Must execute function Show absolutely and only after ResetQuestions
ResetQuestions:function () {
//Great Code Here
}),
I tried this:
initialize: function () {
this.on("Show", this.Show, this);
},
ResetQuestions:function () {
//Great Code Here
this.trigger("Show");
}),
But that was unsuccessful, does anyone know how i can accomplish this?
no need of events you can simply call the function from other function
var sampleView = Backbone.View.extend({
initialize: function () {
this.ResetQuestions();
},
Show: function () {
alert('i am at show');
},
ResetQuestions: function () {
// Execute all you code atlast call Show function as below.
this.Show();
}
});
var view = new sampleView();
var sampleView = Backbone.View.extend({
initialize: function(){
this.ResetQuestions().promise().done(function() { // Using promise here.
this.Show();
});
},
Show: function(){
},
ResetQuestions: function(){
// Execute all you code atlast call Show function as below.
}
});
Then initiate your view,
var view = new sampleView();
Hope this works!!
Perhaps you just got confused what runs what and by naming event and method with same name Show. I have created a jsfiddle with your code - http://jsfiddle.net/yuraji/aqymbeyy/ - you call ResetQuestion method, it triggers Show event, and the Show event runs Show method.
EDIT: I have updated the fiddle to demonstrate that you probably have to bind the methods to the instance, I used _.bindAll for that. If you don't do that you may get event as the context (this).
EDIT: Then, if your ResetQuestions runs asynchronous code, like an ajax request to get new questions, you will have to make sure that your Show event is triggered when the request is completed.

How to test if an event handler is set in a Marionette.js view?

There is a Marionette.js view which acts as a login form. The following code sample shows the relevant code parts including an error I already fixed:
MyApp.module("User", function(User, App, Backbone, Marionette, $, _) {
User.LoginView = Marionette.ItemView.extend({
className: "reveal-modal",
template: "user/login",
ui: {
signInForm: "#signin-form"
},
events: {
"submit #signin-form": "onSignInFormSubmit"
},
onRender: function() {
var self = this;
var $el = this.$el;
// [...] Render schema
_.defer(function(){
$el.reveal({
closeOnBackgroundClick: false,
closed: function(){
self.close(); // <-- This is incorrect. Do not close the ItemView directly!
}
});
});
},
onSignInFormSubmit: function(event) {
event.preventDefault();
var errors = this.signInForm.validate();
var data = this.signInForm.getValue();
// [...] Notify that data has been submitted.
},
hideForm: function() {
this.$el.trigger("reveal:close");
}
});
});
I noticed a major mistake in my implementation. In the callback function closed of Reveal I decided to close the ItemView directly which is wrong as you can read in the documentation of Marionette.js:
View implements a close method, which is called by the region managers automatically.
Bugfix: Instead close() should be called on the region. I fixed this error.
Now I ask myself how can I actually write a test which covers the problem. I use Jasmine for testing. I noticed that the event handler onSignInFormSubmit is no longer called after I have incorrectly closed the ItemView and try to re-submit the form.
Here is a first draft of the test which unfortunately does fail also with the bugfix:
it("should call the submit handler for the sign-in form", function() {
spyOn(userController.loginView, "onSignInFormSubmit");
spyOn(userController.loginView.signInForm, "validate").andCallFake(function(params) {
return null;
});
userController.loginView.hideForm();
userController.loginView.ui.signInForm.trigger("submit");
expect(userController.loginView.onSignInFormSubmit).toHaveBeenCalled();
});
Maybe one could also test if the event handler is registered such as:
expect(userController.loginView.events["submit #signin-form"]).toEqual("onSignInFormSubmit");

Where is this event calling to in MarionetteJS

I am exploring the BBCloneMail demo application for MarionetteJS, but I am not seeing how the events are triggering the rendering actions. I saw some global 'show' event here:
https://github.com/marionettejs/bbclonemail/blob/master/public/javascripts/bbclonemail/components/appController.js#L25
show: function(){
this._showAppSelector("mail");
Marionette.triggerMethod.call(this, "show");
},
But I don't see, where/how the Marionette.triggerMethod results into rendering the Mail component. I was trying to call the triggerMethod for my case, but I get a 'cannot call apply for undefined'. Why is the call above working for the BBcloneMail application.
The Application controller for my case:
MA.AppController = Marionette.Controller.extend({
initialize: function(){
_.bindAll(this, "_showGenres");
},
show: function() {
if (MA.currentUser) {
MA.navbar.show(new MA.Views.Items.LogoutNavbar({model: MA.currentUser}));
}
else
{
MA.navbar.show(new MA.Views.Items.LoginNavbar());
}
this._showGenres();
},
_showGenres: function() {
var categoryNav = new MA.Navigation.Filter({
region: MA.filter
});
this.listenTo(categoryNav, "genre:selected", this._categorySelected);
categoryNav.show();
MA.main.show(MA.composites.movies);
},
showMovieByGenre: function(genre){
var movies = new MA.Controllers.MoviesLib();
that = this;
$.when(movies.getByCategory(genre)).then(that._showMovieList);
Backbone.history.navigate("#movies/genres/" + genre);
},
_showMovieList: function(movieList){
var moviesLib = new MA.Controllers.MoviesLib({
region: MA.main,
movies: movieList
});
Marionette.triggerMethod.call(this, "show");
}
});
I init the application controller in a init.js with:
app = new MA.AppController();
Looking at the source for triggerMethod, this is a way of both triggering an event (the string being passed in), and additionally (if it exists) running a method on the object that has an 'on' prefix.
In your case the error relates to line 560, specifically that there is no method apply on undefined. Based on the code its (in your case) trying to call the equivilent of this.trigger('show') - but AppController doesn't have a method called trigger.
In which case I'm guessing that in the BBCloneMail example this (being bassed into triggerMethod.call) is not actually the controller, but instead the view that is to be shown.

Right way for wiring backbone views

I have a two views:
1 LeftView (maximized when RightView is minimized & vice versa)
2 RightView (containing)
- collection of
- RightItemView (rendering RightItemModel)
When RightView is maximized and the user clicks a RightItemView, I want to maximize LeftView and display something according to the data from the clicked RightItemView.
What's the proper way to wire them?
I would recommend using the Backbone.Events module:
http://backbonejs.org/#Events
Basically, this line is all it takes to create your event dispatcher:
var dispatcher = _.clone(Backbone.Events);
Then all of your views can trigger/listen for events using the global dispatcher.
So, in RightItemView you would do something like this in the click event:
dispatcher.trigger('rightItemClick', data); // data is whatever you need the LeftView to know
Then, in LeftView's initialize function, you can listen for the event and call your relevant function:
dispatcher.on('rightItemClick', this.maximizeAndDisplayData);
Assuming your LeftView would have a function like so:
maximizeAndDisplayData: function(data) {
// do whatever you need to here
// data is what you passed with the event
}
The solution #jordanj77 mentioned is definitely one of the correct ways to achieve your requirement. Just out of curiosity, I thought of another way to achieve the same effect. Instead of using a separate EventDispatcher to communicate between the two views, why shouldn't we use the underlying model as our EventDispatcher? Let's try to think in those lines.
To start with, add a new boolean attribute to the RightItem model called current and default it to false. Whenever, the user selects the RightItemView, set the model's current attribute to true. This will trigger a change:current event on the model.
var RightItem = Backbone.Model.extend({
defaults: {
current: false,
}
});
var RightItemView = Backbone.View.extend({
events: {
'click li': 'changeCurrent'
}
changeCurrent: function() {
this.model.set('current', true);
}
});
On the other side, the LeftView will be handed a Backbone.Collection of RightItem models during creation time. You would anyways have this instance to supply the RightView isn't it? In its initialize method, the LeftView will listen for change:current event. When the event occurs, LeftView will change the current attribute of the model it is currently displaying to false and start displaying the new model that triggered this event.
var LeftView = Backbone.View.extend({
initialize: function() {
this.collection.on('change:current', this.render, this);
},
render: function(model) {
// Avoid events triggered when resetting model to false
if(model.get('current') === true) {
// Reset the currently displayed model
if (this.model) {
this.model.set('current') = false;
}
// Set the currently selected model to the view
this.model = model;
// Display the view for the current model
}
}
});
var leftView = new LeftView({
// Use the collection that you may have given the RightView anyways
collection: rightItemCollection
});
This way, we get to use the underlying model as the means of communication between the Left and Right Views instead of using an EventDispatcher to broker for us.
The solution given by #Ganeshji inspired me to make a live example
I've created 2 views for this.
var RightView = Backbone.View.extend({
el: $('.right_view'),
template: _.template('<p>Right View</p>'),
renderTemplate: function () {
this.$el.html('');
this.$el.append(this.template());
this.$link = this.$el.append('Item to view').children('#left_view_max');
},
events: {
'click #left_view_max' : 'maxLeftView'
},
maxLeftView: function () {
//triggering the event for the leftView
lView.trigger('displayDataInLeftView', this.$link.attr('title'));
},
initialize: function (options) {
this.renderTemplate();
}
});
var LeftView = Backbone.View.extend({
el: $('.left_view'),
template: _.template('<p>Left View</p>'),
renderTemplate: function () {
this.$el.html('');
this.$el.append(this.template());
},
displayDataInLeftView: function (data) {
this.$el.append('<p>' + data + '</p>');
},
initialize: function (options) {
//set the trigger callback
this.on('displayDataInLeftView', this.displayDataInLeftView, this);
this.renderTemplate();
}
});
var lView = new LeftView();
var rView = new RightView();
Hope this helps.

Backbone.js MVC way to render the view AFTER the data is received back from the server on a fetch?

I wish to read a whole database table to fill a Backbone.js Collection, before updating a View.
I am using fetch and listening to the reset event.
My problem is the reset event fires up before the http request is made to the server.
My question is: how can I render the view AFTER the data is received back from the server on a fetch?
Here is a jsfiddle showing the problem (with a debugger placed at reset):
http://jsfiddle.net/GhaPF/16/
The code:
$(document).ready(function() {
var Item = Backbone.Model.extend({
urlRoot : './items'
});
var ItemList = Backbone.Collection.extend({
model: Item,
url: './items/',
});
var ItemListView = Backbone.View.extend({
el: 'body',
initialize: function(myitemList) {
this.itemlist = myitemList;
this.itemlist.bind('reset', this.debuggThis());
},
debuggThis: function() {
debugger;
},
render: function() {
},
events: {
"keypress #new-item": "createOnEnter"
},
createOnEnter: function(e) {
}
});
$("#new-item").focus();
var itemlist = new ItemList();
var myitemListView = new ItemListView(itemlist);
itemlist.fetch();
});​
The following code works, but it just doesn't feel like proper backbone.js (MVC) code since it would be placed outside of the View definition:
itemlist.fetch().complete(function(){
Maybe the issue is this line:
this.itemlist.bind('reset', this.debuggThis());
Should actually be:
this.itemlist.bind('reset', this.debuggThis);
Your debugThis function was getting run at the time you set up the listener for the 'reset' event - not when the event is triggered. This was telling JavaScript that you wanted debugThis to return a callback function instead of having debugThis "be" the callback function.
Also, orangewarp's comment about passing 'this' as the third parameter is probably relevant too. Sot it would end up as:
this.itemlist.bind('reset', this.debuggThis, this);
That's strange. When you fetch() the reset event should be triggered AFTER your collection is populated. So I'm thinking the phenomena that reset happens before the http request is fired up may not be what you think it is.
Instead of using the complete... you could always just use the success callback option like this:
itemlist.fetch({
success: function() {
// Whatever code you want to run.
itemlist.debuggThis();
}
});
Also, when binding your reset you probably want this:
this.itemlist.bind('reset', this.debuggThis, this);

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