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See how fast (or not) your plugins and loaders are, so you can optimise your builds
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WrappedPlugin Fix memory leak in WrappedPlugin Apr 6, 2018
__tests__ Add a file, and try to make contribution generally a … Dec 26, 2018
.gitignore Add in some functional tests, using Lerna to manage the dependencies … Mar 8, 2018
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loader.js Granular loader data (#17) Feb 18, 2018
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neutrino.js Add in explicit support for Neutrino, and include an examples folder Mar 4, 2018
output.js Use chalk for colour output, in order for better terminal colour supp… Feb 20, 2018
package-lock.json Bump the version to 1.3.1 Mar 19, 2019
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utils.test.js Granular loader data (#17) Feb 18, 2018

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


npm install --save-dev speed-measure-webpack-plugin


yarn add -D speed-measure-webpack-plugin


SMP requires at least Node v6. But otherwise, accepts all webpack versions (1, 2, 3, and 4).


Change your webpack config from

const webpackConfig = {
  plugins: [
    new MyPlugin(),
    new MyOtherPlugin()


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.


Pass these into the constructor, as an object:

const smp = new SpeedMeasurePlugin(options);


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.


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


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


Type: Object
Default: {}

By default, SMP derives plugin names through 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.

const uglify = new UglifyJSPlugin();
const smp = new SpeedMeasurePlugin({
  pluginNames: {
    customUglifyName: uglify

const webpackConfig = smp.wrap({
  plugins: [

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.


Contributors are welcome! 😊

Please check out the


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



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