In my backbone app, I need to provide a fallback for each required file, in the case that the CDN that delivers them fails.

I have tried overwriting require.onError like so:

require.onError = function (err) {

    if (err.requireType === 'timeout') {

        var url = err.requireModules;



        if (!!~url.indexOf(jquery/))

            console.warn(CDN timed out, falling back to local jQuery.js)

            require([libs/jquery]);

            return;

        if (!!~url.indexOf(jqueryui/))

            console.warn(CDN timed out, falling back to local jQueryUI.js)

            require([libs/jqueryui]);

            return;

        if (!!~url.indexOf(underscore))

            console.warn(CDN timed out, falling back to local underscore.js)

            require([libs/underscore]);

            return;

        if (!!~url.indexOf(backbone))

            console.warn(CDN timed out, falling back to local backbone.js)

            require([libs/backbone]);

            return;

    }

}

The problem is that this will asynchronously load the fallback files. I need these files to load in order, just like the original require statement, where I use the order! plugin.

With the overridden onError: when the CDN fails to load, the fallback load is started, but not waited for. This presents a problem because the scripts are ordered to be loaded based on their dependencies. Here is a look at my original require statement, that depends on the CDN:

require([

    order!http://ajax.googleapis.com/ajax/libs/jquery/1.7.2/jquery.min.js,

    order!http://ajax.googleapis.com/ajax/libs/jqueryui/1.8.23/jquery-ui.min.js,

    order!http://cdnjs.cloudflare.com/ajax/libs/underscore.js/1.3.3/underscore-min.js,

    order!http://cdnjs.cloudflare.com/ajax/libs/backbone.js/0.9.2/backbone-min.js,

    order!utils/date,

    order!core/core,

    order!core/errors,

    order!core/constants

], function() {

    ...

}