Backbone.js progress bar while fetching collection

Question

i'd like to show a progress bar while i update the app with fresh content. I guess the best thing to do would be to do it while calling .fetch on a collection.

The content i fetch is primarily images (video poster etc) but i only get the link, not a base64 string or something big. What i would like to do is overlay the screen with a progress bar while fetching the image links, render the view so all images are ready and then the overlay should go away and show the app with the fresh content already loaded.

Now i have no idea how i could build a progress bar for this since i am not really getting images directly but only the link and then rendering the view.

Answer 1

Try this:

var SomeView = Backbone.View.extend({
    loadStuff: function(){
        var self = this;
        someModel.fetch({
            xhr: function() {
                var xhr = $.ajaxSettings.xhr();
                xhr.onprogress = self.handleProgress;
                return xhr;
            }
        });
    },
    handleProgress: function(evt){
        var percentComplete = 0;
        if (evt.lengthComputable) {  
            percentComplete = evt.loaded / evt.total;
        }
        //console.log(Math.round(percentComplete * 100)+"%");
    }
});