_SystemJS 0.20.0-alpha.1 is now available with performance improvements and Web Assembly support. [Try it out here](https://github.com/systemjs/systemjs/releases/tag/0.20.0-alpha.1)._
Universal dynamic module loader - loads ES6 modules, AMD, CommonJS and global scripts in the browser and NodeJS.
* [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](https://github.com/ModuleLoader/es6-module-loader/blob/master/docs/loader-config.md#paths-implementation), [bundles](docs/production-workflows.md#bundle-extension) and [global shims](docs/module-formats.md#shim-dependencies).
* [Loader plugins](docs/overview.md#plugin-loaders) allow custom transpilation or asset loading.
Built to the format ES6-specified loader API from [ES6 Specification Draft Rev 27, Section 15](http://wiki.ecmascript.org/doku.php?id=harmony:specification_drafts#august_24_2014_draft_rev_27),
and will be updated to the [WhatWG loader API](https://whatwg.github.io/loader/) as soon as it can be considered stable for implementation.
~19KB minified and gzipped, runs in IE8+ and NodeJS.
For discussion, join the [Gitter Room](https://gitter.im/systemjs/systemjs).
SystemJS relies on `Promise` being present in the environment.
For the best performance in IE and older browsers, it is advisable to load a polyfill like [Bluebird](https://github.com/petkaantonov/bluebird) or [es6-promise](https://github.com/stefanpenner/es6-promise) before SystemJS.
Otherwise, when Promise is not available, SystemJS will attempt to load the `system-polyfills.js` file located in the dist folder which contains the when.js Promise polyfill.
### NodeJS
To load modules in NodeJS, install SystemJS with:
```
npm install systemjs
```
If transpiling ES6, also install the transpiler plugin, following the instructions from the transpiler project page.
We can then load modules equivalently in NodeJS as we do in the browser:
```javascript
var SystemJS = require('systemjs');
// loads './app.js' from the current directory
SystemJS.import('./app.js').then(function(m) {
console.log(m);
});
```
If you are using jspm as a package manager you will also need to load the generated configuration.
The best way to do this in node is to get your `System` instance through jspm, which will automatically load your config correctly for you:
