jQuery files dependencies loader

dependencies.js

/**
 * By - Yair Even-Or (2017)  MIT license
 * loads, using jQuery, dependency files.
 * @param  {Object}  settings [files (Array), baseDir (String), sync (Boolean)]
 * @return {Object}           [promise]
 */
window.dependencies = {
    /**
     * @param  {Object/Array} settings [either a "settings" object or a simple Array of files to load]
     * @return {Object}                [jQuery AJAX (promise)]
     */
    load: function(opts) {
        var settings = {
            files: [],
            baseDir: '',
            sync: false
        };

        if (typeof opts == 'string')
            settings.files = [opts];

        // settings can also be a simple Array of strings (files to load)
        else if (opts instanceof Array && opts.length) {
            settings.files = opts;
        } else if (opts instanceof Object)
            $.extend(settings, opts);

        // for invalid inputs (return a rejected promise)
        else if (!opts || !opts.files || !opts.files.length)
            return (new $.Deferred()).reject();

        return this[settings.sync ? "sync" : "async"](settings);
    },

    /**
     * loads files asynchronously, regardless of their order
     * @return {Object} [promise]
     */
    async: function(settings) {
        var dependenciesDeferreds = [];

        settings.files.forEach(function(path) {
            var promise = $.ajax({ url: '/' + settings.baseDir + path });
            dependenciesDeferreds.push(promise);
        })

        return $.when(...dependenciesDeferreds);
    },

    /**
     * loads file synchronously (slower)
     * @return {Object} [promise]
     */
    sync: function(settings) {
        var deferred = new $.Deferred();

        // reverse the Array order so "pop" method could be used and the load order would be correct
        settings.files = settings.files.reverse();

        function recursiveLoad(path) {
            if (path)
                $.ajax({ url: '/' + settings.baseDir + path }).done(onDone)
            else
                deferred.resolve();
        }

        function onDone() {
            recursiveLoad(settings.files.pop());
        }

        onDone();

        return deferred;
    }
};