webpack.config.js

'use strict';
var webpack = require('webpack');

var config = {
  context: __dirname + '/src', // `__dirname` is root of project and `src` is source
  entry: {
    app: './app.js',
  },
  output: {
    path: __dirname + '/dist', // `dist` is the destination
    filename: 'bundle.js',
    publicPath: "/",
  },
  plugins: [
    /* prevent that webpack loads momentjs-support for all languages. Only DE and EN.
     * see http://stackoverflow.com/questions/25384360/how-to-prevent-moment-js-from-loading-locales-with-webpack
     */
    new webpack.ContextReplacementPlugin(/moment[\\\/]locale$/, /^\.\/(de|en)$/),
  ],
  module: {
    rules: [{
        test: /node_modules[\\\/]vis[\\\/].*\.js$/, // vis.js files
        loader: 'babel-loader',
        query: {
          cacheDirectory: true,
          presets: [ "babel-preset-es2015" ].map(require.resolve),
          plugins: [
            "transform-es3-property-literals", // see https://github.com/almende/vis/pull/2452
            "transform-es3-member-expression-literals", // see https://github.com/almende/vis/pull/2566
            "transform-runtime" // see https://github.com/almende/vis/pull/2566
          ]
        }
      }, {
        test: /\.js$/, //Check for all js files
        loader: 'babel-loader',
        query: {
          presets: [ "babel-preset-es2015" ].map(require.resolve)
        }
      }, {
        test: /\.css$/,
        use: [
          'style-loader',
          'css-loader'
        ]
      }, {
        test: /.*\.png$/i,
        loaders: [ 'file-loader', {
          loader: 'image-webpack-loader',
          query: {
            progressive: true,
            pngquant: {
              quality: '65-90',
              speed: 4
            }
          }
        }
      ]
      }
    ]
  },
  //To run development server
  devServer: {
    contentBase: __dirname + '/src',
  },

  devtool: "eval-source-map" // Default development sourcemap
};

// Check if build is running in production mode, then change the sourcemap type
if (process.env.NODE_ENV === "production") {
  config.devtool = "source-map";

  // Can do more here
  // JSUglify plugin
  // Offline plugin
  // Bundle styles seperatly using plugins etc,
}

module.exports = config;