webpack.config.babel.js

import webpack from 'webpack';
import path from 'path';
import HtmlWebpackPlugin from 'html-webpack-plugin';
import FlowStatusWebpackPlugin from 'flow-status-webpack-plugin';

const HTMLWebpackPluginConfig = new HtmlWebpackPlugin({
  template: path.join(__dirname, '/app/index.html'),
  filename: 'index.html',
  inject: 'body',
});

const PATHS = {
  app: path.join(__dirname, 'app'),
  build: path.join(__dirname, 'dist'),
};

const LAUNCH_COMMAND = process.env.npm_lifecycle_event;

const isProduction = LAUNCH_COMMAND === 'production';

process.env.BABEL_ENV = LAUNCH_COMMAND;

const productionPlugin = new webpack.DefinePlugin({
  'process.env': {
    NODE_ENV: JSON.stringify('production'),
  },
});

const base = {
  entry: [
    PATHS.app,
  ],
  output: {
    path: PATHS.build,
    filename: 'index_bundle.js',
  },
  module: {
    loaders: [
      { test: /\.js$/, exclude: /node_modules/, loader: 'babel-loader' },
      { test: /\.css$/, loader: 'style!css?sourceMap&modules&localIdentName=[name]__[local]___[hash:base64:5]' },
    ],
  },
};

const developmentConfig = {
  devtool: 'cheap-module-inline-source-map',
  devServer: {
    contentBase: PATHS.build,
    hot: true,
    inline: true,
    progress: true,
    historyApiFallback: true,
  },
  plugins: [HTMLWebpackPluginConfig, new webpack.HotModuleReplacementPlugin(), new FlowStatusWebpackPlugin()],
};

const productionConfig = {
  devtool: 'cheap-module-source-map',
  plugins: [HTMLWebpackPluginConfig, productionPlugin],
};

export default Object.assign({}, base,
  isProduction === true ? productionConfig : developmentConfig
);