Webpack Karma using react/addons

Question

I have a large-ish Angular app written in Typescript generating JS files 1:1 plus external modules such as moment and React loaded off the same server. Dependencies are handled by RequireJS.

We added some basic Angular Karma tests which worked fine. This uses a duplicate RequireJS config tweaked to load the tests into Karma.

Now I am trying to test some React components and in the process move to Webpack. So, I have modified the Karma config to use Webpack and installed the external dependencies using npm. I have spent all day trying to get this to work but I cannot find a solution which works for my setup.

karma.conf.js

var path = require('path');

module.exports = function (config) {
    config.set({

        // base path that will be used to resolve all patterns (eg. files, exclude)
        basePath: '',


        // frameworks to use
        // available frameworks: https://npmjs.org/browse/keyword/karma-adapter
        frameworks: ['jasmine', 'requirejs'],

        // list of files / patterns to load in the browser
        files: [
            'ng/*.js',
            'ng/**/*.js',
            'ng/**/tests/*.spec.js'


        ],


        // list of files to exclude
        exclude: [
                'app.js', // Old requirejs config
           ],


        // preprocess matching files before serving them to the browser
        // available preprocessors: https://npmjs.org/browse/keyword/karma-preprocessor
        preprocessors: {
            '*.js': ['webpack', 'sourcemap'],
            'ng/**/*.js': ['webpack', 'sourcemap'],
            'partials/**/*.html': ['ng-html2js']
        },


   webpack: { //kind of a copy of your webpack config
      devtool: 'inline-source-map', //just do inline source maps instead of the default
      module: {
        loaders: [
          {
            test: /\.js$/,
            loader: 'babel',
            exclude: path.resolve(__dirname, 'node_modules'),
            query: {
              presets: ['airbnb']
            }
          },
          {
            test: /\.json$/,
            loader: 'json',
          },
          {
            test: /\.ts$/,
            loader: 'typescript',
          },
        ],
      },

      externals: {
        'react': true,
        'react/addons': true,
        'react/lib/ExecutionEnvironment': true,
        'react/lib/ReactContext': true
      }
    },

    webpackServer: {
      noInfo: true //please don't spam the console when running in karma!
    },


        // test results reporter to use
        // possible values: 'dots', 'progress'
        // available reporters: https://npmjs.org/browse/keyword/karma-reporter
        reporters: ['progress'],


        // web server port
        port: 9876,


        // enable / disable colors in the output (reporters and logs)
        colors: true,


        // level of logging
        // possible values: config.LOG_DISABLE || config.LOG_ERROR || config.LOG_WARN || config.LOG_INFO || config.LOG_DEBUG
        logLevel: config.LOG_INFO,


        // enable / disable watching file and executing tests whenever any file changes
        autoWatch: true,


        // start these browsers
        // available browser launchers: https://npmjs.org/browse/keyword/karma-launcher
        browsers: ['PhantomJS',
                   'Chrome'
                ],

        plugins: [
             'karma-webpack',
             'karma-sourcemap-loader',
             'karma-requirejs',
             'karma-ng-html2js-preprocessor',

             //'karma-firefox-launcher',
             'karma-chrome-launcher',
             'karma-phantomjs-launcher',
             'karma-jasmine'
        ],

    babelPreprocessor: {
      options: {
        presets: ['airbnb']
      }
    },

        // Continuous Integration mode
        // if true, Karma captures browsers, runs the tests and exits
        singleRun: false,

        // Concurrency level
        // how many browser should be started simultanous
        concurrency: Infinity,

    });
};

This is what I am getting:

PhantomJS 2.1.1 (Linux 0.0.0) ERROR
  ReferenceError: Can't find variable: react
  at /vagrant/app/media/website/js/ng/chartApp.js:48060 <- webpack:/external "react/addons":1:0

How should I be setting this up?

Answer 1

This might be happening if you're using Enzyme, which uses some lazy require() calls to maintain compatibility with React 0.13 and 0.14, so Webpack isn't bundling them.

If that's the case, put this in your karma.config.js :

webpack: { // ...whatever else you have... externals: { 'cheerio': 'window', 'react/addons': true, 'react/lib/ExecutionEnvironment': true, 'react/lib/ReactContext': true } }

If you're not using Enzyme, this might still be a solution (at least the react/addons part).

See this Karma page for details.

Answer 2

Here's your first problem:

"I have a large-ish Angular app written in Typescript generating JS files 1:1 plus external modules such as moment and React loaded off the same server. Dependencies are handled by RequireJS ."