Source: loaders/loader.js

var ResourceLoader = require('resource-loader'),
    textureParser = require('./textureParser'),
    spritesheetParser = require('./spritesheetParser'),
    bitmapFontParser = require('./bitmapFontParser');

/**
 *
 * The new loader, extends Resource Loader by Chad Engler : https://github.com/englercj/resource-loader
 *
 * ```js
 * var loader = PIXI.loader; // pixi exposes a premade instance for you to use.
 * //or
 * var loader = new PIXI.loaders.Loader(); // you can also create your own if you want
 *
 * loader.add('bunny',"data/bunny.png");
 *
 * loader.once('complete',onAssetsLoaded);
 *
 * loader.load();
 * ```
 *
 * @class
 * @extends PIXI.ResourceLoader
 * @memberof PIXI.loaders
 * @param [baseUrl=''] {string} The base url for all resources loaded by this loader.
 * @param [concurrency=10] {number} The number of resources to load concurrently.
 */
function Loader(baseUrl, concurrency)
{
    ResourceLoader.call(this, baseUrl, concurrency);

    for (var i = 0; i < Loader._pixiMiddleware.length; ++i) {
        this.use(Loader._pixiMiddleware[i]());
    }
}

Loader.prototype = Object.create(ResourceLoader.prototype);
Loader.prototype.constructor = Loader;

module.exports = Loader;

Loader._pixiMiddleware = [
    // parse any blob into more usable objects (e.g. Image)
    ResourceLoader.middleware.parsing.blob,
    // parse any Image objects into textures
    textureParser,
    // parse any spritesheet data into multiple textures
    spritesheetParser,
    // parse any spritesheet data into multiple textures
    bitmapFontParser
];

Loader.addPixiMiddleware = function (fn) {
    Loader._pixiMiddleware.push(fn);
};

// Add custom extentions
var Resource = ResourceLoader.Resource;

Resource.setExtensionXhrType('fnt', Resource.XHR_RESPONSE_TYPE.DOCUMENT);