Webpack stats plugin for build information, file manifests, etc.


Webpack Stats Plugin

Build Status

This plugin will ingest the webpack stats object, process / transform the object and write out to a file for further consumption.

The most common use case is building a hashed bundle and wanting to programmatically refer to the correct bundle path in your Node.js server.


The plugin is available via npm:

$ npm install --save webpack-stats-plugin


You can see lots of examples at demo/webpack.config.js.


var StatsWriterPlugin = require("webpack-stats-plugin").StatsWriterPlugin;

module.exports = {
  plugins: [
    // Everything else **first**.

    // Write out stats file to build directory.
    new StatsWriterPlugin({
      filename: "stats.json" // Default

Custom Transform Function

The transform function has a signature of:

 * Transform skeleton.
 * @param {Object} data           Stats object
 * @param {Object} opts           Options
 * @param {Object} opts.compiler  Current compiler instance
 * @returns {String}              String to emit to file
function (data, opts) {}

which you can use like:

var StatsWriterPlugin = require("webpack-stats-plugin").StatsWriterPlugin;

module.exports = {
  plugins: [
    new StatsWriterPlugin({
      transform: function (data, opts) {
        return JSON.stringify({
          main: data.assetsByChunkName.main[0],
          css: data.assetsByChunkName.main[1]
        }, null, 2);



  • opts (Object) options
  • opts.filename (String) output file name (Default: "stat.json")
  • opts.fields (Array) fields of stats obj to keep (Default: ["assetsByChunkName"])
  • opts.transform (Function) transform stats obj (Default: JSON.stringify())

Stats writer module.

Stats can be a string or array (we"ll have array from using source maps):

"assetsByChunkName": {
  "main": [

Note: The stats object is big. It includes the entire source included in a bundle. Thus, we default opts.fields to ["assetsByChunkName"] to only include those. However, if you want the whole thing (maybe doing an opts.transform function), then you can set fields: null in options to get all of the stats object.


filename: The opts.filename option can be a file name or path relative to output.path in webpack configuration. It should not be absolute.

transform: By default, the retrieved stats object is JSON.stringify'ed but by supplying an alternate transform you can target any output format. See demo/webpack.config.js for various examples including Markdown output.

  • Warning: The output of transform should be a String, not an object. On Node v4.x if you return a real object in transform, then webpack will break with a TypeError (See #8). Just adding a simple JSON.stringify() around your object is usually what you need to solve any problems.


Contributions welcome! Make sure to pass $ gulp check.