JSPM

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  • License MIT

Tiny async loader for modern browsers

Package Exports

  • loadjs
  • loadjs/dist/loadjs.min.js

This package does not declare an exports field, so the exports above have been automatically detected and optimized by JSPM instead. If any package subpath is missing, it is recommended to post an issue to the original package (loadjs) to support the "exports" field. If that is not possible, create a JSPM override to customize the exports field for this package.

Readme

LoadJS

LoadJS is a tiny async loader for modern browsers (654 bytes).

Dependency Status devDependency Status

Introduction

LoadJS is a tiny async loading library for modern browsers (IE9+). It has a simple yet powerful dependency management system that lets you fetch JavaScript and CSS files in parallel and execute code after the dependencies have been met. The recommended way to use LoadJS is to include the minified source code in your <html> and then use the loadjs global to manage JavaScript dependencies after pageload.

LoadJS is based on the excellent $script library by Dustin Diaz. We kept the behavior of the library the same but we re-wrote the code from scratch to add support for success/error callbacks and to optimize the library for modern browsers. LoadJS is 654 bytes (minified + gzipped).

Here's an example of what you can do with LoadJS:

// define a dependency bundle
loadjs(['/path/to/foo.js', '/path/to/bar.js'], 'foobar');

// execute code elsewhere when the bundle has loaded
loadjs.ready('foobar', {
  success: function() { /* foo.js & bar.js loaded */ },
  error: function(depsNotFound) { /* foobar bundle load failed */ }
});

The latest version of LoadJS can be found in the dist/ directory in this repository:

You can also use it as a CJS or AMD module:

$ npm install --save-dev loadjs
var loadjs = require('loadjs');

loadjs(['/path/to/foo.js', '/path/to/bar.js'], 'foobar');

loadjs.ready('foobar', {
  success: function() { /* foo.js & bar.js loaded */ },
  error: function(depsNotFound) {/* foobar bundle load failed */}
});

Browser Support

  • IE9+ (async: false support only works in IE10+)
  • Opera 12+
  • Safari 5+
  • Chrome
  • Firefox
  • iOS 6+
  • Android 4.4+

LoadJS also detects script load failures from AdBlock Plus and Ghostery in:

  • Safari
  • Chrome

Note: LoadJS treats empty CSS files as load failures in IE (to get around lack of support for onerror events on <link> tags)

Documentation

  1. Load a single file
loadjs('/path/to/foo.js', {
  success: function() { /* foo.js loaded */}
});
  1. Fetch files in parallel and load them asynchronously
loadjs(['/path/to/foo.js', '/path/to/bar.js'], {
  success: function() { /* foo.js & bar.js loaded */ }
});
  1. Fetch files in parallel and load them in series
loadjs(['/path/to/foo.js', '/path/to/bar.js'], {
  success: function() { /* foo.js and bar.js loaded in series */ },
  async: false
});
  1. Fetch JavaScript and CSS files
loadjs(['/path/to/foo.css', '/path/to/bar.js'], {
  success: function() { /* foo.css and bar.js loaded */ }
});
  1. Add a bundle id
loadjs(['/path/to/foo.js', '/path/to/bar.js'], 'foobar', {
  success: function() { /* foo.js & bar.js loaded */ }
});
  1. Add an error callback
loadjs(['/path/to/foo.js', '/path/to/bar.js'], 'foobar', {
  success: function() { /* foo.js & bar.js loaded */ },
  error: function(pathsNotFound) { /* at least one path didn't load */ }
});
  1. Execute a callback after bundle finishes loading
loadjs(['/path/to/foo.js', '/path/to/bar.js'], 'foobar');

loadjs.ready('foobar', {
  success: function() { /* foo.js & bar.js loaded */ }
});
  1. Chain .ready() together
loadjs('/path/to/foo.js', 'foo');
loadjs('/path/to/bar.js', 'bar');

loadjs
  .ready('foo', {
    success: function() { /* foo.js loaded */ }
  })
  .ready('bar', {
    success: function() { /* bar.js loaded */ }
  });
  1. Compose more complex dependency lists
loadjs('/path/to/foo.js', 'foo');
loadjs('/path/to/bar.js', 'bar');
loadjs(['/path/to/thunkor.js', '/path/to/thunky.js'], 'thunk');

// wait for multiple depdendencies
loadjs.ready(['foo', 'bar', 'thunk'], {
  success: function() {
    // foo.js & bar.js & thunkor.js & thunky.js loaded
  },
  error: function(depsNotFound) {
    if (depsNotFound.indexOf('foo') > -1) {};  // foo failed
    if (depsNotFound.indexOf('bar') > -1) {};  // bar failed
    if (depsNotFound.indexOf('thunk') > -1) {};  // thunk failed
  }
});
  1. Use .done() for more control
loadjs.ready('my-awesome-plugin', {
  success: function() {
    myAwesomePlugin();
  }
});

loadjs.ready('jquery', {
  success: function() {
    // plugin requires jquery
    window.myAwesomePlugin = function() {
      if (!window.jQuery) throw "jQuery is missing!";
    };

    // plugin is done loading
    loadjs.done('my-awesome-plugin');
  }
});

Directory structure

loadjs/
├── dist
│   ├── loadjs.js
│   ├── loadjs.min.js
│   └── loadjs.umd.js
├── examples
├── gulpfile.js
├── LICENSE.txt
├── package.json
├── README.md
├── src
│   └── loadjs.js
├── test
└── umd-templates

Development Quickstart

  1. Install dependencies
  1. Clone repository
$ git clone git@github.com:muicss/loadjs.git
$ cd loadjs
  1. Install node dependencies using npm
$ npm install
  1. Build examples
$ ./node_modules/.bin/gulp examples:build

To view the examples you can use any static file server. To use the nodejs http-server module:

$ npm install http-server
$ ./node_modules/.bin/http-server -p 3000

Then visit http://localhost:3000/examples

  1. Build distribution files
$ ./node_modules/.bin/gulp dist:build

The files will be located in the dist directory.

Run tests

To run the browser tests first build the loadjs library:

$ ./node_modules/.bin/gulp test:build

Then visit http://localhost:3000/test