Asset.images - Handle image load errors

[kuralj]

Asset.images will not fire onComplete if there is an issue with any of the images passed to it (eg. server issue, missing file, incorrect filename).

Any associated progress bar will also not display correctly because onProgress is not called for image errors.

The issue occurs because counter++ and onProgress is only called for image.onload. Adding an onerror function that duplicates the onload functionality would solve this.

Case scenario: If you wanted to preload images for a UI, then init the UI when the images are loaded, a single image error would mean the UI would never display.

Sample fix:

images: function(sources, options){
	options = $merge({
		onComplete: $empty,
		onProgress: $empty
	}, options);
	if (!sources.push) sources = [sources];
	var images = [];
	var counter = 0;
	sources.each(function(source){
		var img = new Asset.image(source, {
			'onload': function(){
				options.onProgress.call(this, counter, sources.indexOf(source));
				counter++;
				if (counter == sources.length) options.onComplete();
			},
			'onerror': function(){
				// could pass a flag to onProgress indicating that the image failed
				options.onProgress.call(this, counter, sources.indexOf(source));
				counter++;
				if (counter == sources.length) options.onComplete();
			}
		});
		images.push(img);
	});
	return new Elements(images);
}

[lgladdy]

This should probably be added to the 'Notes' section of the 1.2 documentation - I spent a couple of hours trying to figure out why it wasn't firing!

[lgladdy]

Ops, adding a comment set component to core - changing to plugins.