A minimalist frontend resource loader that you can actually understand and extend.

725 bytes (gzip)

Notice: urw-loader is expected to be used in an environment which has Promise and common Array methods.

sample code

By default, a urw loader recognize strings as javascript file uri and load them by <script async> tags.

a simple loader

var loader = new URW
var promise1 = loader.load(
  ['http://s0.cdn.net/zepto.js', 'http://s0.cdn.net/hammer.js'],
  'http://s0.cdn.net/paidui/page.js',
  function initPage () {
    // use zepto, hammer, page.js
  }
)
/* the timeline for above code */
// ====zepto=====
// ====hammer=====
//                  ===page.js====
//                                   initPage()

use middlewares

var loader = new URW({
  domain: '//s0.cdn.net/'
})

loader.use(function addext (resource) {
  return resource + '.js'
}).use(function comboGroup (resource) {
  return this.config.domain + '?combo=' + resource.join()
}).use(function timing (resource, progress) {
    var start = Date.now()
    progress.then(function () {
        console.info('urw timing:', Date.now() - start, resource)
    })
})

var promise2 = loader.load(
  ['zepto', 'hammer'],
  'paidui/page'
).then(function initPage () {})

loadable resources

String, function, Promise and Array are loadable.

download method

You can overwrite the URW.util.load or loader.util.load method to change the download method, e.g. when you want to load js by xhr or load css.