scriptjs

What is scriptjs?

scriptjs is a JavaScript library that allows you to asynchronously load JavaScript files. It provides a simple and efficient way to manage script dependencies and ensure that scripts are loaded in the correct order.

What are scriptjs's main functionalities?

Asynchronous Script Loading

This feature allows you to load external JavaScript files asynchronously. The callback function is executed once the script is fully loaded.

const $script = require('scriptjs');
$script('https://example.com/some-script.js', function() {
  console.log('Script loaded!');
});

Loading Multiple Scripts

You can load multiple scripts at once and execute a callback function when all scripts are loaded.

const $script = require('scriptjs');
$script(['https://example.com/script1.js', 'https://example.com/script2.js'], function() {
  console.log('Both scripts loaded!');
});

Named Bundles

This feature allows you to name script bundles and execute a callback when the entire bundle is ready.

const $script = require('scriptjs');
$script('https://example.com/some-script.js', 'bundle1');
$script.ready('bundle1', function() {
  console.log('Bundle1 is ready!');
});

Other packages similar to scriptjs

requirejs

RequireJS is a JavaScript file and module loader. It is optimized for in-browser use, but it can be used in other JavaScript environments, such as Rhino and Node. Compared to scriptjs, RequireJS offers more advanced features like module definitions and dependency management.

headjs

HeadJS is a JavaScript library that allows you to load scripts and stylesheets asynchronously. It also provides features for managing script dependencies and executing code when scripts are ready. Compared to scriptjs, HeadJS offers additional features like stylesheet loading and more advanced dependency management.

loadjs

LoadJS is a tiny async loader for modern browsers. It provides a simple API for loading JavaScript files and managing dependencies. Compared to scriptjs, LoadJS is more lightweight and focuses solely on script loading without additional features.

README

$script.js - Async JavaScript loader & dependency manager

$script.js is an asynchronous JavaScript loader and dependency manager with an astonishingly impressive lightweight footprint. Like many other script loaders, $script.js allows you to load script resources on-demand from any URL and not block other resources from loading (like CSS and images). Furthermore, it's unique interface allows developers to work easily with even the most complicated dependencies, which can often be the case for large, complex web applications.

Browser Support

• IE 6+
• Opera 10+
• Safari 3+
• Chrome 1+
• Firefox 2+

Examples

old school - blocks CSS, Images, AND JS!

<script src="jquery.js"></script>
<script src="my-jquery-plugin.js"></script>
<script src="my-app-that-uses-plugin.js"></script>

middle school - loads as non-blocking, but has multiple dependents

$script('jquery.js', function () {
  $script('my-jquery-plugin.js', function () {
    $script('my-app-that-uses-plugin.js')
  })
})

new school - loads as non-blocking, and ALL js files load asynchronously

// load jquery and plugin at the same time. name it 'bundle'
$script(['jquery.js', 'my-jquery-plugin.js'], 'bundle')

// load your usage
$script('my-app-that-uses-plugin.js')


/*--- in my-jquery-plugin.js ---*/
$script.ready('bundle', function() {
  // jquery & plugin (this file) are both ready
  // plugin code...
})


/*--- in my-app-that-uses-plugin.js ---*/
$script.ready('bundle', function() {
  // use your plugin :)
})

Exhaustive list of ways to use $script.js

$script('foo.js', function() {
  // foo.js is ready
})


$script(['foo.js', 'bar.js'], function() {
  // foo.js & bar.js is ready
})


$script(['foo.js', 'bar.js'], 'bundle')
$script.ready('bundle', function() {
  // foo.js & bar.js is ready
})

// create an id and callback inline
$script(['foo.js', 'bar.js'], 'bundle', function () {
  // foo.js & bar.js is ready
})


$script('foo.js', 'foo')
$script('bar.js', 'bar')
$script
  .ready('foo', function() {
    // foo.js is ready
  })
  .ready('bar', function() {
    // bar.js is ready
  })


var dependencyList = {
    foo: 'foo.js'
  , bar: 'bar.js'
  , thunk: ['thunkor.js', 'thunky.js']
}

$script('foo.js', 'foo')
$script('bar.js', 'bar')

// wait for multiple depdendencies!
$script.ready(['foo', 'bar', 'thunk'], function () {
  // foo.js & bar.js & thunkor.js & thunky.js is ready
}, function(depsNotFound) {
    // foo.js & bar.js may have downloaded
    // but ['thunk'] dependency was never found
    // so lazy load it now
    depsNotFound.forEach(function(dep) {
      $script(dependencyList[dep], dep)
    })
  })


// in my-awesome-plugin.js
$script.ready('jquery', function() {
  //define awesome jquery plugin here
  $script.done('my-awesome-plugin')
})

// in index.html
$script('jquery.js', 'jquery')
$script('my-awesome-plugin.js')
$script.ready('my-awesome-plugin', function() {
  //run code here when jquery and my awesome plugin are both ready
})

$script.path()

Optionally to make working with large projects easier, there is a path variable you can set to set as a base.

$script.path('/js/modules/')
$script(['dom', 'event'], function () {
  // use dom & event
});

Note that this will include all scripts from here on out with the base path. If you wish to circumvent this for any single script, you can simply call $script.get()

$script.path('/js/modules/')
$script(['dom', 'event'], function () {
  // use dom & event
})

$script.get('http://example.com/base.js', function () {

})

$script.urlArgs()

As of 2.5.5 it's possible to concat URL arguments (i.e. a query string) to the script path. This is especially useful when you're in need of a cachebuster and works as follows:

$script.urlArgs('key=value&foo=bar');

Please note that Squid, a popular proxy, doesn’t cache resources with a querystring. This hurts performance when multiple users behind a proxy cache request the same file – rather than using the cached version everybody would have to send a request to the origin server. So ideally, as Steve Souders points out, you should rev the filename itself.

Developers

Building a $script environment works like this:

npm install -dev
make

Ender support

You can add $script to your existing ender build by adding it as such:

ender add scriptjs

Get access to it as such:

$.require(...)

You can also require it as such:

var $S = require('scriptjs')

$S('/foo.js', function () {
  // foo is ready
})