Backbone 0.9.9: Difference between listenTo and on

JavascriptEventsbackbone.jsBackbone Events

Javascript Problem Overview


I am trying to learn the new changes they did in Backbone 0.9.9.

Currently I got problems to understand the difference between listenTo and on:

listenTo

var View = Backbone.View.extend({

    tagName: "div",

    intialize: function() {
        this.listenTo(this.model, 'change', this.render);
    },

    render: function() {
        this.$el.empty();
        this.$el.append('<p>hello world</p>');
    }

});

on

var View = Backbone.View.extend({

    tagName: "div",

    intialize: function() {
        this.model.on('change', this.render, this);
    },

    render: function() {
        this.$el.empty();
        this.$el.append('<p>hello world</p>');
    }

});

I have heard that listenTo allows with stopListening to unsubscribe from all events when for example the view gets removed to avoid memory leaks.

Is this the only reason?

Javascript Solutions


Solution 1 - Javascript

When you create a view, both listenTo and on add event handling. However, when the view is destroyed, the listenTo call will automatically remove the event handler. This prevents memory leaks and zombie event listeners.

So, use on if you want to manage the handler yourself. Just make sure to call off. Otherwise, call listenTo.

Solution 2 - Javascript

listenTo and stopListening came from the community, basically. They help to make it easier to bind and unbind events.

There's a lot of existing documentation and blog posts surrounding the idea, including stuff that I've written on the subject.

Johnny Oshika is the first person that I saw using this technique. It was originally posted as an answer to a StackOverflow question here: https://stackoverflow.com/questions/7567404/backbone-js-repopulate-or-recreate-the-view/7607853#7607853

You can read what I've written about this, here:

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Content TypeOriginal AuthorOriginal Content on Stackoverflow
QuestionbodokaiserView Question on Stackoverflow
Solution 1 - JavascriptRichardView Answer on Stackoverflow
Solution 2 - JavascriptDerick BaileyView Answer on Stackoverflow