# Webpack Manifest Plugin [![Build Status](https://travis-ci.org/danethurber/webpack-manifest-plugin.svg?branch=master)](https://travis-ci.org/danethurber/webpack-manifest-plugin)  [![codecov](https://codecov.io/gh/danethurber/webpack-manifest-plugin/badge.svg?branch=master)](https://codecov.io/gh/danethurber/webpack-manifest-plugin?branch=master) [![Gitter](https://img.shields.io/gitter/room/nwjs/nw.js.svg)](https://gitter.im/webpack-manifest-plugin#)


Webpack plugin for generating an asset manifest.

## Install

```bash
npm install --save-dev webpack-manifest-plugin
```

## Usage

In your `webpack.config.js`

```javascript
var ManifestPlugin = require('webpack-manifest-plugin');

module.exports = {
    // ...
    plugins: [
      new ManifestPlugin()
    ]
};
```

This will generate a `manifest.json` file in your root output directory with a mapping of all source file names to their corresponding output file, for example:

```json
{
  "mods/alpha.js": "mods/alpha.1234567890.js",
  "mods/omega.js": "mods/omega.0987654321.js"
}
```


## Configuration

A manifest is configurable using constructor options:

```javascript
new ManifestPlugin({
  fileName: 'my-manifest.json',
  basePath: '/app/'
  seed: {
    name: 'My Manifest'
  }
})
```


## Options:

### `fileName`

Type: `String`<br>
Default: `manifest.json`

The manifest filename in your output directory.


### `basePath`

Type: `String`

A path prefix for all file references. Useful for including your output path in the manifest.


### `publicPath`

Type: `String`

A path prefix used only on output files, similar to Webpack's  [output.publicPath](https://github.com/webpack/docs/wiki/configuration#outputpublicpath). Ignored if `basePath` was also provided.


### `stripSrc`

Type: `String`, `RegExp`

Removes unwanted strings from source filenames.


### `writeToFileEmit`

Type: `Boolean`<br>
Default: `false`

If set to `true` will emit to build folder and memory in combination with `webpack-dev-server`


### `seed`

Type: `Object`<br>
Default: `{}`

A cache of key/value pairs to used to seed the manifest. This may include a set of [custom key/value](https://developer.mozilla.org/en-US/Add-ons/WebExtensions/manifest.json) pairs to include in your manifest, or may be used to combine manifests across compilations in [multi-compiler mode](https://github.com/webpack/webpack/tree/master/examples/multi-compiler). To combine manifests, pass a shared seed object to each compiler's ManifestPlugin instance.

### `filter`

Type: `function`

Filter out files. [more details](#hooks-options)


### `map`

Type: `function`

Modify files details before the manifest is created. [more details](#hooks-options)


### `reduce`

Type: `function`<br>
Default: `(manifest, {name, path}) => ({...manifest, [name]: path})`

Create the manifest. It can return anything as long as it's serialisable by `JSON.stringify`. Use the `seed` options to populate `manifest`. [more details](#hooks-options)


## Hooks Options

`filter`, `map`, `reduce` takes as an input an Object with the following properties:

### `path`

Type: `String`


### `chunk`

Type: [`Chunk`](https://github.com/webpack/webpack/blob/master/lib/Chunk.js)


### `name`

Type: `String`, `null`


### `isChunk`

Type: `Boolean`


### `isInitial`

Type: `Boolean`

Is required to run you app. Cannot be `true` if `isChunk` is `false`.


### `isAsset`

Type: `Boolean`


### `isModuleAsset`

Type: `Boolean`

Is required by a module. Cannot be `true` if `isAsset` is `false`.


## License

MIT © [Dane Thurber](https://github.com/danethurber)