grunt-rollup/README.md

# grunt-rollup
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> Grunt plugin for [rollup](https://github.com/rollup/rollup) - next-generation ES6 module bundler

## Getting Started
This plugin requires Grunt `>=0.4.0`

If you haven't used [Grunt](http://gruntjs.com/) before, be sure to check out the [Getting Started](http://gruntjs.com/getting-started) guide, as it explains how to create a [Gruntfile](http://gruntjs.com/sample-gruntfile) as well as install and use Grunt plugins. Once you're familiar with that process, you may install this plugin with this command:

```shell
npm install grunt-rollup --save-dev
```

Once the plugin has been installed, it may be enabled inside your Gruntfile with this line of JavaScript:

```js
grunt.loadNpmTasks('grunt-rollup');
```

## The "rollup" task

### Overview
In your project's Gruntfile, add a section named `rollup` to the data object passed into `grunt.initConfig()`.

```js
grunt.initConfig({
  rollup: {
    options: {
      // Task-specific options go here.
    },
    your_target: {
      // Target-specific file lists and/or options go here.
    },
  },
});
```

### Options

Supports all the options from [rollup's JavaScript API](https://github.com/rollup/rollup/wiki/JavaScript-API).


### Sourcemaps
A value of `true` for `sourceMap` will output the map to a file with the same name as the JavaScript with `.map` appended. A value of `inline` for `sourceMap` will inline the sourcemap into the source file.

To get relative paths, set `sourceMapRelativePaths` to `true`. This sets rollup `sourceMapFile` property, making the sourcemap relative to the output file.

### Usage Examples

```js
grunt.initConfig({
  rollup: {
    options: {},
    files: {
      'dest/bundle.js': ['src/entry.js'], // Only one source file is permitted
    },
  },
});
```

### Usage with Plugins

```js
var babel = require('rollup-plugin-babel');

grunt.initConfig({
  rollup: {
    options: {
      plugins: [
        babel({
          exclude: './node_modules/**'
        })
      ]
    },
    files: {
      'dest':'dest/bundle.js',
      'src' : 'src/entry.js', // Only one source file is permitted
    },
  },
});
```

#### Plugin getter

Some plugins are stateful and this doesn't play nice with multiple bundles. For example the `rollup-plugin-babel` plugin keeps a track of used `babel` helpers, and passing the configured plugin only once will cause the helpers to leak from one bundle to another. To prevent that, pass a function that returns an array of plugins, like this:

```js
var babel = require('rollup-plugin-babel');

grunt.initConfig({
  rollup: {
    options: {
      plugins: function() {
        return [
          babel({
            exclude: './node_modules/**'
          })
        ];
      }
    },
    files: {
      'dest/bundle.js': 'src/entry.js',
      'dest/bundle2.js': 'src/entry2.js',
    },
  },
});
```

This way the plugin will be refreshed for each bundle.

## Contributing
In lieu of a formal styleguide, take care to maintain the existing coding style. Add unit tests for any new or changed functionality. Lint and test your code using [Grunt](http://gruntjs.com/).

## Releasing

```bash
npm version minor && git push --tags origin master && npm publish
```