SystemJS
========

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_For upgrading to SystemJS 0.17 / 0.18, see the [SystemJS 0.17 release upgrade notes for more information](https://github.com/systemjs/systemjs/releases/tag/0.17.0), or read the updated [SystemJS Overview](docs/overview.md) guide._

Universal dynamic module loader - loads ES6 modules, AMD, CommonJS and global scripts in the browser and NodeJS. Works with both Traceur and Babel.

* [Loads any module format](docs/module-formats.md) with [exact circular reference and binding support](https://github.com/ModuleLoader/es6-module-loader/blob/v0.17.0/docs/circular-references-bindings.md).
* Loads [ES6 modules compiled into the `System.register` bundle format for production](docs/production-workflows.md), maintaining circular references support.
* Supports RequireJS-style [map](docs/overview.md#map-config), [paths](docs/overview.md#paths-config), [bundles](docs/production-workflows.md#bundle-extension) and [global shims](docs/module-formats.md#shim-dependencies).
* [Loader plugins](docs/overview.md#plugins) allow loading assets through the module naming system such as CSS, JSON or images.

Built on top of the [ES6 Module Loader polyfill](https://github.com/ModuleLoader/es6-module-loader).

~12KB minified and gzipped, runs in IE8+ and NodeJS.

For discussion, [see the Google Group](https://groups.google.com/group/systemjs).

For a list of guides and tools, see the [Third-Party Resources Wiki](https://github.com/systemjs/systemjs/wiki/Third-Party-Resources).

Documentation
---

* [ES6 Modules Overview](docs/es6-modules-overview.md)
* [SystemJS Overview](docs/overview.md)
* [Config API](docs/config-api.md)
* [Module Formats](docs/module-formats.md)
* [Production Workflows](docs/production-workflows.md)
* [System API](docs/system-api.md)
* [Creating Plugins](docs/creating-plugins.md)

Basic Use
---

### Browser

```html
<script src="system.js"></script>
<script>
  // set our baseURL reference path
  System.config({
    baseURL: '/app'
  });

  // loads /app/main.js
  System.import('main.js');
</script>
```

To load ES6, locate a transpiler ([`traceur.js`](https://github.com/jmcriffey/bower-traceur), ['browser.js' from Babel](https://github.com/babel/babel), or ['typescript.js' from TypeScript](https://github.com/Microsoft/TypeScript)) 
in the baseURL path, then set the transpiler:

```html
<script>
  System.config({
    // or 'traceur' or 'typescript'
    transpiler: 'babel'
    // or traceurOptions or typescriptOptions
    babelOptions: {

    }
  });
</script>
```

Alternatively a custom path to Babel or Traceur can also be set through paths:

```javascript
System.config({
  map: {
    traceur: 'path/to/traceur.js'
  }
});
```

### Polyfills

SystemJS relies on `Promise` and `URL` being present in the environment. When these are not available it will send a request out to the `system-polyfills.js` file located in the dist folder which will polyfill `window.Promise` and `window.URLPolyfill`.

This is typically necessary in IE, so ensure to keep this file in the same folder as SystemJS.

Alternatively the polyfills can be loaded manually or via other polyfill implementations as well.

### NodeJS

To load modules in NodeJS, install SystemJS with:

```
  npm install systemjs
```

If transpiling ES6, also install the transpiler:

```
  npm install traceur babel typescript 
```

We can then load modules equivalently to in the browser:

```javascript
var System = require('systemjs');

System.transpiler = 'traceur';

// loads './app.js' from the current directory
System.import('./app').then(function(m) {
  console.log(m);
});
```

If using TypeScript, set `global.ts = require('typescript')` before importing to ensure it is loaded correctly.

### Plugins

Supported loader plugins:

* [CSS](https://github.com/systemjs/plugin-css) `System.import('my/file.css')`
* [Image](https://github.com/systemjs/plugin-image) `System.import('some/image.png!image')`
* [JSON](https://github.com/systemjs/plugin-json) `System.import('some/data.json')`
* [Text](https://github.com/systemjs/plugin-text) `System.import('some/text.txt!text')`

Additional Plugins:

* [CoffeeScript](https://github.com/forresto/plugin-coffee) `System.import('./test.coffee')`
* [Jade](https://github.com/johnsoftek/plugin-jade)
* [JSX](https://github.com/floatdrop/plugin-jsx) `System.import('template.jsx')`
* [Markdown](https://github.com/guybedford/plugin-md) `System.import('app/some/project/README.md').then(function(html) {})`
* [WebFont](https://github.com/guybedford/plugin-font) `System.import('google Port Lligat Slab, Droid Sans !font')`
* [Handlebars](https://github.com/davis/plugin-hbs) `System.import('template.hbs!')`
* [Ember Handlebars](https://github.com/n-fuse/plugin-ember-hbs) `System.import('template.hbs!')`

[Read about using plugins here](docs/overview.md#plugin-loaders)
[Read the guide here on creating plugins](docs/creating-plugins.md).

#### Running the tests

To install the dependencies correctly, run `bower install` from the root of the repo, then open `test/test.html` in a browser with a local server
or file access flags enabled.

License
---

MIT

[travis-url]: https://travis-ci.org/systemjs/systemjs
[travis-image]: https://travis-ci.org/systemjs/systemjs.svg?branch=master