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# compression-webpack-plugin
Prepare compressed versions of assets to serve them with Content-Encoding.
## Getting Started
To begin, you'll need to install `compression-webpack-plugin`:
```console
$ npm install compression-webpack-plugin --save-dev
```
Then add the plugin to your `webpack` config. For example:
**webpack.config.js**
```js
const CompressionPlugin = require('compression-webpack-plugin');
module.exports = {
plugins: [new CompressionPlugin()],
};
```
And run `webpack` via your preferred method.
## Options
| Name | Type | Default | Description |
| :-------------------------------------------------: | :---------------------------------------: | :---------------: | :------------------------------------------------------------------------------------------------------------ |
| **[`test`](#test)** | `{String\|RegExp\|Array<String\|RegExp>}` | `undefined` | Include all assets that pass test assertion |
| **[`include`](#include)** | `{String\|RegExp\|Array<String\|RegExp>}` | `undefined` | Include all assets matching any of these conditions |
| **[`exclude`](#exclude)** | `{String\|RegExp\|Array<String\|RegExp>}` | `undefined` | Exclude all assets matching any of these conditions |
| **[`algorithm`](#algorithm)** | `{String\|Function}` | `gzip` | The compression algorithm/function |
| **[`compressionOptions`](#compressionoptions)** | `{Object}` | `{ level: 9 }` | Compression options for `algorithm` |
| **[`threshold`](#threshold)** | `{Number}` | `0` | Only assets bigger than this size are processed (in bytes) |
| **[`minRatio`](#minratio)** | `{Number}` | `0.8` | Only assets that compress better than this ratio are processed (`minRatio = Compressed Size / Original Size`) |
| **[`filename`](#filename)** | `{String\|Function}` | `[path][base].gz` | The target asset filename |
| **[`deleteOriginalAssets`](#deleteoriginalassets)** | `{Boolean}` | `false` | Whether to delete the original assets or not |
| **[`cache`](#cache)** | `{Boolean}` | `true` | Enable file caching |
### `test`
Type: `String|RegExp|Array<String|RegExp>`
Default: `undefined`
Include all assets that pass test assertion.
**webpack.config.js**
```js
module.exports = {
plugins: [
new CompressionPlugin({
test: /\.js(\?.*)?$/i,
}),
],
};
```
### `include`
Type: `String|RegExp|Array<String|RegExp>`
Default: `undefined`
Include all assets matching any of these conditions.
**webpack.config.js**
```js
module.exports = {
plugins: [
new CompressionPlugin({
include: /\/includes/,
}),
],
};
```
### `exclude`
Type: `String|RegExp|Array<String|RegExp>`
Default: `undefined`
Exclude all assets matching any of these conditions.
**webpack.config.js**
```js
module.exports = {
plugins: [
new CompressionPlugin({
exclude: /\/excludes/,
}),
],
};
```
### `algorithm`
Type: `String|Function`
Default: `gzip`
The compression algorithm/function.
> ℹ️ If you use custom function for the `algorithm` option, the default value of the `compressionOptions` option is `{}`.
#### `String`
The algorithm is taken from [zlib](https://nodejs.org/api/zlib.html).
**webpack.config.js**
```js
module.exports = {
plugins: [
new CompressionPlugin({
algorithm: 'gzip',
}),
],
};
```
#### `Function`
Allow to specify a custom compression function.
**webpack.config.js**
```js
module.exports = {
plugins: [
new CompressionPlugin({
algorithm(input, compressionOptions, callback) {
return compressionFunction(input, compressionOptions, callback);
},
}),
],
};
```
### `compressionOptions`
Type: `Object`
Default: `{ level: 9 }`
Compression options for `algorithm`.
You can find all options here [zlib](https://nodejs.org/api/zlib.html#zlib_class_options).
> ℹ️ If you use custom function for the `algorithm` option, the default value is `{}`.
**webpack.config.js**
```js
module.exports = {
plugins: [
new CompressionPlugin({
compressionOptions: { level: 1 },
}),
],
};
```
### `threshold`
Type: `Number`
Default: `0`
Only assets bigger than this size are processed. In bytes.
**webpack.config.js**
```js
module.exports = {
plugins: [
new CompressionPlugin({
threshold: 8192,
}),
],
};
```
### `minRatio`
Type: `Number`
Default: `0.8`
Only assets that compress better than this ratio are processed (`minRatio = Compressed Size / Original Size`).
Example: you have `image.png` file with 1024b size, compressed version of file has 768b size, so `minRatio` equal `0.75`.
In other words assets will be processed when the `Compressed Size / Original Size` value less `minRatio` value.
You can use `1` value to process assets that are smaller than the original.
Use a value of `Infinity` to process all assets even if they are larger than the original size or their original size is `0` bytes (useful when you are pre-zipping all assets for AWS).
Use a value of `Number.MAX_SAFE_INTEGER` to process all assets even if they are larger than the original size, excluding assets with their original size is `0` bytes.
**webpack.config.js**
```js
module.exports = {
plugins: [
new CompressionPlugin({
// Compress all assets, including files with `0` bytes size
// minRatio: Infinity
// Compress all assets, excluding files with `0` bytes size
// minRatio: Number.MAX_SAFE_INTEGER
minRatio: 0.8,
}),
],
};
```
### `filename`
Type: `String|Function`
Default: `"[path][base].gz"`
The target asset filename.
#### `String`
For example we have `assets/images/image.png?foo=bar#hash`:
`[path]` is replaced with the directories to the original asset, included trailing `/` (`assets/images/`).
`[file]` is replaced with the path of original asset (`assets/images/image.png`).
`[base]` is replaced with the base (`[name]` + `[ext]`) of the original asset (`image.png`).
`[name]` is replaced with the name of the original asset (`image`).
`[ext]` is replaced with the extension of the original asset, included `.` (`.png`).
`[query]` is replaced with the query of the original asset, included `?` (`?foo=bar`).
`[fragment]` is replaced with the fragment (in the concept of URL it is called `hash`) of the original asset (`#hash`).
**webpack.config.js**
```js
module.exports = {
plugins: [
new CompressionPlugin({
filename: '[path][base].gz',
}),
],
};
```
#### `Function`
**webpack.config.js**
```js
module.exports = {
plugins: [
new CompressionPlugin({
filename(pathData) {
// The `pathData` argument contains all placeholders - `path`/`name`/`ext`/etc
// Available properties described above, for the `String` notation
if (/\.svg$/.test(pathData.file)) {
return 'assets/svg/[path][base].gz';
}
return 'assets/js/[path][base].gz';
},
}),
],
};
```
### `deleteOriginalAssets`
Type: `Boolean`
Default: `false`
Whether to delete the original assets or not.
**webpack.config.js**
```js
module.exports = {
plugins: [
new CompressionPlugin({
deleteOriginalAssets: true,
}),
],
};
```
### `cache`
> ⚠ Ignored in webpack 5! Please use https://webpack.js.org/configuration/other-options/#cache.
Type: `Boolean|String`
Default: `true`
Enable file caching.
The default path to cache directory: `node_modules/.cache/compression-webpack-plugin`.
#### `Boolean`
Enable/disable file caching.
**webpack.config.js**
```js
module.exports = {
plugins: [
new CompressionPlugin({
cache: true,
}),
],
};
```
#### `String`
Enable file caching and set path to cache directory.
**webpack.config.js**
```js
module.exports = {
plugins: [
new CompressionPlugin({
cache: 'path/to/cache',
}),
],
};
```
## Examples
### Using Zopfli
Prepare compressed versions of assets using `zopfli` library.
> ℹ️ `@gfx/zopfli` require minimum `8` version of `node`.
To begin, you'll need to install `@gfx/zopfli`:
```console
$ npm install @gfx/zopfli --save-dev
```
**webpack.config.js**
```js
const zopfli = require('@gfx/zopfli');
module.exports = {
plugins: [
new CompressionPlugin({
compressionOptions: {
numiterations: 15,
},
algorithm(input, compressionOptions, callback) {
return zopfli.gzip(input, compressionOptions, callback);
},
}),
],
};
```
### Using Brotli
[Brotli](https://en.wikipedia.org/wiki/Brotli) is a compression algorithm originally developed by Google, and offers compression superior to gzip.
Node 10.16.0 and later has [native support](https://nodejs.org/api/zlib.html#zlib_zlib_createbrotlicompress_options) for Brotli compression in its zlib module.
We can take advantage of this built-in support for Brotli in Node 10.16.0 and later by just passing in the appropriate `algorithm` to the CompressionPlugin:
**webpack.config.js**
```js
const zlib = require('zlib');
module.exports = {
plugins: [
new CompressionPlugin({
filename: '[path][base].br',
algorithm: 'brotliCompress',
test: /\.(js|css|html|svg)$/,
compressionOptions: {
// zlib’s `level` option matches Brotli’s `BROTLI_PARAM_QUALITY` option.
level: 11,
},
threshold: 10240,
minRatio: 0.8,
deleteOriginalAssets: false,
}),
],
};
```
**Note** The `level` option matches `BROTLI_PARAM_QUALITY` [for Brotli-based streams](https://nodejs.org/api/zlib.html#zlib_for_brotli_based_streams)
### Multiple compressed versions of assets for different algorithm
**webpack.config.js**
```js
const zlib = require('zlib');
module.exports = {
plugins: [
new CompressionPlugin({
filename: '[path][base].gz',
algorithm: 'gzip',
test: /\.js$|\.css$|\.html$/,
threshold: 10240,
minRatio: 0.8,
}),
new CompressionPlugin({
filename: '[path][base].br',
algorithm: 'brotliCompress',
test: /\.(js|css|html|svg)$/,
compressionOptions: {
level: 11,
},
threshold: 10240,
minRatio: 0.8,
}),
],
};
```
## Contributing
Please take a moment to read our contributing guidelines if you haven't yet done so.
[CONTRIBUTING](./.github/CONTRIBUTING.md)
## License
[MIT](./LICENSE)
[npm]: https://img.shields.io/npm/v/compression-webpack-plugin.svg
[npm-url]: https://npmjs.com/package/compression-webpack-plugin
[node]: https://img.shields.io/node/v/compression-webpack-plugin.svg
[node-url]: https://nodejs.org
[deps]: https://david-dm.org/webpack-contrib/compression-webpack-plugin.svg
[deps-url]: https://david-dm.org/webpack-contrib/compression-webpack-plugin
[tests]: https://github.com/webpack-contrib/compression-webpack-plugin/workflows/compression-webpack-plugin/badge.svg
[tests-url]: https://github.com/webpack-contrib/compression-webpack-plugin/actions
[cover]: https://codecov.io/gh/webpack-contrib/compression-webpack-plugin/branch/master/graph/badge.svg
[cover-url]: https://codecov.io/gh/webpack-contrib/compression-webpack-plugin
[chat]: https://img.shields.io/badge/gitter-webpack%2Fwebpack-brightgreen.svg
[chat-url]: https://gitter.im/webpack/webpack
[size]: https://packagephobia.now.sh/badge?p=compression-webpack-plugin
[size-url]: https://packagephobia.now.sh/result?p=compression-webpack-plugin