Proudly maintained and developed by the team at 18ways.
AI-powered runtime localisation and i18n infrastructure.
The first step to optimising your webpack build speed, is to know where to focus your attention.
This plugin measures your webpack build speed, giving an output like this:
## Install
```bash
npm install --save-dev speed-measure-webpack-plugin
```
or
```bash
yarn add -D speed-measure-webpack-plugin
```
## Requirements
SMP requires at least **Node v6**. But otherwise, accepts **all webpack** versions (1, 2, 3, 4, and 5).
To work on the repository itself and run the test suite, use **Node v18+**.
## Usage
Change your webpack config from
```javascript
const webpackConfig = {
plugins: [new MyPlugin(), new MyOtherPlugin()],
};
```
to
```javascript
const SpeedMeasurePlugin = require("speed-measure-webpack-plugin");
const smp = new SpeedMeasurePlugin();
const webpackConfig = smp.wrap({
plugins: [new MyPlugin(), new MyOtherPlugin()],
});
```
and you're done! SMP will now be printing timing output to the console by default.
Check out the [examples folder](/examples) for some more examples.
## Options
Pass these into the constructor, as an object:
```javascript
const smp = new SpeedMeasurePlugin(options);
```
### `options.disable`
Type: `Boolean`
Default: `false`
If truthy, this plugin does nothing at all.
`{ disable: !process.env.MEASURE }` allows opt-in measurements with `MEASURE=true npm run build`.
### `options.outputFormat`
Type: `String|Function`
Default: `"human"`
Determines in what format this plugin prints its measurements
- `"json"` - produces a JSON blob
- `"human"` - produces a human readable output
- `"humanVerbose"` - produces a more verbose version of the human readable output
- If a function, it will call the function with the JSON blob, and output the response
### `options.outputTarget`
Type: `String|Function`
Default: `console.log`
- If a string, it specifies the path to a file to output to.
- If a function, it will call the function with the output as the first parameter
### `options.pluginNames`
Type: `Object`
Default: `{}`
By default, SMP derives plugin names through `plugin.constructor.name`. For some
plugins this doesn't work (or you may want to override this default). This option
takes an object of `pluginName: PluginConstructor`, e.g.
```javascript
const uglify = new UglifyJSPlugin();
const smp = new SpeedMeasurePlugin({
pluginNames: {
customUglifyName: uglify,
},
});
const webpackConfig = smp.wrap({
plugins: [uglify],
});
```
### `options.excludedPlugins`
Type: `Array`
Default: `[]`
Excludes plugins from SMP's proxy wrapping. Entries can be:
- a plugin name
- a plugin constructor
- a regular expression matched against plugin names
Name matching checks both `options.pluginNames` aliases and constructor names. E.g.
```javascript
const smp = new SpeedMeasurePlugin({
pluginNames: {
customReactRefresh: reactRefreshPlugin,
},
excludedPlugins: [
"customReactRefresh",
MiniCssExtractPlugin,
/SomeLegacyPlugin$/,
],
});
```
### `options.loaderTopFiles`
Type: `Number`
Default: `0`
You can configure SMP to include the files that take the most time per loader, when using `outputFormat: 'humanVerbose'`. E.g., to show the top 10 files per loader:
```javascript
const smp = new SpeedMeasurePlugin({
outputFormat: "humanVerbose",
loaderTopFiles: 10,
});
```
### `options.compareLoadersBuild`
Type: `Object`
Default: `{}`
This option gives you a comparison over time of the module count and time spent, per loader. This option provides more data when `outputFormat: "humanVerbose"`.
Given a required `filePath` to store the build information, this option allows you to compare differences to your codebase over time. E.g.
```javascript
const smp = new SpeedMeasurePlugin({
compareLoadersBuild: {
filePath: "./buildInfo.json",
},
});
```
### `options.granularLoaderData` _(experimental)_
Type: `Boolean`
Default: `false`
By default, SMP measures loaders in groups. If truthy, this plugin will give per-loader timing information.
This flag is _experimental_. Some loaders will have inaccurate results:
- loaders using separate processes (e.g. `thread-loader`)
- loaders emitting file output (e.g. `file-loader`)
We will find solutions to these issues before removing the _(experimental)_ flag on this option.
### `options.excludedLoaders`
Type: `Array`
Default: `[]`
When you enable `granularLoaderData`, SMP prepends its timing loader to each matching
loader rule. Use this option to skip rules whose loader chain contains a matching
loader name or regular expression. String matching checks both the original loader
request and the normalized package name. E.g.
```javascript
const smp = new SpeedMeasurePlugin({
granularLoaderData: true,
excludedLoaders: ["thread-loader", /mini-css-extract-plugin/],
});
```
## FAQ
### What does general output time mean?
This tends to be down to webpack reading in from the file-system, but in general it's anything outside of what SMP can actually measure.
### What does modules without loaders mean?
It means vanilla JS files, which webpack can handle out of the box.
## Contributing
Contributors are welcome!
Please check out the [CONTRIBUTING.md](./CONTRIBUTING.md).
## Migrating
SMP follows [semver](https://semver.org/). If upgrading a major version, you can consult [the migration guide](./migration.md).
## License
[MIT](/LICENSE)
## Contributors ✨
Thanks goes to these wonderful people ([emoji key](https://allcontributors.org/docs/en/emoji-key)):
Stephen Cook
scarletsky
牛さん
Thomas Bentkowski
Alan Agius
Ximing
Tan Li Hau ⚠️
Björn Brauer
Suraj Patel
Jm ⚠️
This project follows the [all-contributors](https://github.com/all-contributors/all-contributors) specification. Contributions of any kind welcome!