Using mochapack with jsdom

jsdom is a JavaScript based headless browser that can be used to create a realistic testing environment.

For the best experience with jsdom, it is recommended that you load a document into the global scope before running everything else. This can be done in four simple steps.

First of all you need to install jsdom (Note: This guide uses jsdom in version 9.9.1.)

For npm

$ npm install jsdom --save-dev

For yarn

$ yarn add --dev jsdom

Then create a helper script to prepare the jsdom environment, e.g. setup.js.


const jsdom = require('jsdom').jsdom;

global.document = jsdom('');
global.window = document.defaultView;
window.console = global.console;

Object.keys(document.defaultView).forEach((property) => {
  if (typeof global[property] === 'undefined') {
    global[property] = document.defaultView[property];

global.navigator = {
  userAgent: 'node.js'

As next you need to make sure that the compile target in your Webpack configuration is node. This makes sure that Node can interpret Webpack's code properly and that you have access to node features like fs, global, process, etc.


var nodeExternals = require('webpack-node-externals');

module.exports = {
  target: 'node', // webpack should emit node.js compatible code
  externals: [nodeExternals()], // in order to ignore all modules in node_modules folder from bundling

And finally use it with the command line using the --require and --webpack-config option:

$ mochapack --require setup.js --webpack-config webpack-config.test.js

Node.js Compatibility

jsdom requires Node 4 or above. If you are stuck using an older version of Node, you may want to try using a browser-based test runner such as Karma Webpack.