webpack.config.js

const path = require('path');
const webpack = require('webpack');
const ExtractTextPlugin = require('extract-text-webpack-plugin');

const byExtension = (obj) => Object.keys(obj).map((k) => Object.assign({
  test: new RegExp(`\.(${k})$`),
}, obj[k]));

if (process.env.NODE_ENV === 'production' && !process.env.API_URL) {
  throw new Error('when NODE_ENV is "production", API_URL must be set');
}

module.exports = {
  devtool: 'source-map',
  entry: {
    browser: [ 'babel-polyfill', './src/entry-browser' ],
  },
  output: {
    path: path.join(__dirname, 'build'),
    filename: '[name]-bundle.js',
    publicPath: '/',
  },
  plugins: [
    new webpack.DefinePlugin({
      'process.env.NODE_ENV': JSON.stringify(process.env.NODE_ENV || 'development'),
      'process.env.API_URL': JSON.stringify(process.env.API_URL || ''),
    }),
  ],
  module: {
    loaders: byExtension({
      'css': {
        loaders: [ 'style', 'css?modules' ],
      },
      'woff2?(\\?v=[0-9]\\.[0-9]\\.[0-9])?': {
        loaders: [ 'url?limit=10000&mimetype=application/font-woff' ],
      },
      '(ttf|eot|svg)(\\?v=[0-9]\\.[0-9]\\.[0-9])?': {
        loaders: [ 'file' ],
      },
      'js': {
        loaders: [ 'babel' ],
        include: path.join(__dirname, 'src'),
      },
      'jpg': {
        loaders: [ 'url?limit=10000&mimetype=image/jpeg', 'image-webpack' ],
      },
      'png': {
        loaders: [ 'url?limit=10000&mimetype=image/png', 'image-webpack' ],
      },
    }),
  },
  resolve: {
    extensions: ['', '.js'],
    alias: {
      actions: path.join(__dirname, 'src', 'actions'),
      components: path.join(__dirname, 'src', 'components'),
      constants: path.join(__dirname, 'src', 'constants'),
      containers: path.join(__dirname, 'src', 'containers'),
      lib: path.join(__dirname, 'src', 'lib'),
      reducers: path.join(__dirname, 'src', 'reducers'),
      schema: path.join(__dirname, 'src', 'schema'),
    },
  },
};

if (process.env.NODE_ENV === 'production') {
  module.exports.output.filename = '[name]-bundle-[hash].js';
  module.exports.plugins.push(new ExtractTextPlugin('styles-[hash].css'));

  module.exports.module.loaders.forEach((loader) => {
    if (loader.loaders.indexOf('style') === 0) {
      loader.loader = ExtractTextPlugin.extract(...loader.loaders);
      delete loader.loaders;
    }
  });
}