Speed Measure Plugin

^{(for webpack)}

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:

!Preview of Speed Measure Plugin's output

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, and 4).

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 for some more examples.

Options

Pass these into the constructor, as an object:

`javascript
const smp = new SpeedMeasurePlugin(options);
`

$3

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.

$3

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

$3

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

$3

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],
});
`

$3

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,
});
`

$3

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",
},
});
`

$3

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.

FAQ

$3

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.

$3

It means vanilla JS files, which webpack can handle out of the box.

Contributing

Contributors are welcome! 😊

Please check out the CONTRIBUTING.md.

Migrating

SMP follows semver. If upgrading a major version, you can consult the migration guide.

License

MIT

Contributors ✨

Thanks goes to these wonderful people (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 specification. Contributions of any kind welcome!