webpack.config.js

const path              = require('path');
const merge             = require('webpack-merge');
const webpack           = require('webpack');
const NpmInstallPlugin  = require('npm-install-webpack-plugin');
const HtmlWebpackPlugin = require('html-webpack-plugin');
const CleanPlugin       = require('clean-webpack-plugin');
const ExtractTextPlugin = require('extract-text-webpack-plugin');

// Load *package.json* so we can use `dependencies` from there
const pkg = require('./package.json');

const TARGET           = process.env.npm_lifecycle_event;

const PATHS = {
  app: path.join(__dirname, 'app'),
  build: path.join(__dirname, 'build'),
  style: path.join(__dirname, 'app/main.css')
};

process.env.BABEL_ENV = TARGET;

const common = {
  // Entry accepts a path or an object of entries. We'll be using the
  // latter form given it's convenient with more complex configurations.
  entry: {
    app: PATHS.app,
    style: PATHS.style
  },
  // Add resolve.extensions.
  // '' is needed to allow imports without an extension.
  // Note the .'s before extensions as it will fail to match without!!!
  resolve: {
    extensions: ['', '.js', '.jsx']
  },
  output: {
    path: PATHS.build,

    // Output using entry name
    filename: '[name].js'
  },
  module: {
    loaders: [
       // Set up jsx. This accepts js too thanks to RegExp
      {
        test: /\.jsx?$/,
        // Enable caching for improved performance during development
        // It uses default OS directory by default. If you need something
        // more custom, pass a path to it. I.e., babel?cacheDirectory=<path>
        loaders: ['babel?cacheDirectory'],
        // Parse only app files! Without this it will go through entire project.
        // In addition to being slow, that will most likely result in an error.
        include: PATHS.app
      }
    ]
  },
  plugins: [
    new HtmlWebpackPlugin({
      template: 'node_modules/html-webpack-template/index.ejs',
      title: 'Kanban app',
      appMountId: 'app',
      inject: false
    })
  ]
};

// Default configuration
if(TARGET === 'start' || !TARGET) {
  module.exports = merge(common, {
    devtool: 'eval-source-map',
    devServer: {

      // Enable history API fallback so HTML5 History API based
      // routing works. This is a good default that will come
      // in handy in more complicated setups.
      historyApiFallback: true,
      hot: true,
      inline: true,
      progress: true,

      // Display only errors to reduce the amount of output.
      stats: 'errors-only',

      // Parse host and port from env so this is easy to customize.
      //
      // If you use Vagrant or Cloud9, set
      // host: process.env.HOST || '0.0.0.0';
      //
      // 0.0.0.0 is available to all network devices unlike default
      // localhost
      host: process.env.HOST,
      port: process.env.PORT
    },
    module: {
      loaders: [
        // Define development specific CSS setup
        {
          test: /\.css$/,
          loaders: ['style', 'css'],
          include: PATHS.app
        }
      ]
    },
    plugins: [
      new webpack.HotModuleReplacementPlugin(),
      new NpmInstallPlugin({
        save: true // --save
      })
    ]
  });
}

if(TARGET === 'build' || TARGET === 'stats') {
  module.exports = merge(common, {
    // Define vendor entry point needed for splitting
    entry: {
      vendor: Object.keys(pkg.dependencies).filter(function(v) {
        // Exclude alt-utils as it won't work with this setup
        // due to the way the package has been designed
        // (no package.json main).
        return v !== 'alt-utils';
      })
    },
    output: {
      path: PATHS.build,
      filename: '[name].[chunkhash].js',
      chunkFilename: '[chunkhash].js'
    },
    module: {
      loaders: [
        // Extract CSS during build
        {
          test: /\.css$/,
          loader: ExtractTextPlugin.extract('style', 'css'),
          include: PATHS.app
        }
      ]
    },
    plugins: [

      new CleanPlugin([PATHS.build], {
        verbose: false // Don't write logs to console
      }),

      // Output extracted CSS to a file
      new ExtractTextPlugin('[name].[chunkhash].css'),
      
      // Extract vendor and manifest files
      new webpack.optimize.CommonsChunkPlugin({
        names: ['vendor', 'manifest']
      }),

      // Setting DefinePlugin affects React library size!
      // DefinePlugin replaces content "as is" so we need some extra quotes
      // for the generated code to make sense
      new webpack.DefinePlugin({
        'process.env.NODE_ENV': '"production"'

        // You can set this to JSON.stringify('development') for your
        // development target to force NODE_ENV to development mode
        // no matter what
      }),
      new webpack.optimize.UglifyJsPlugin({
        compress: {
          warnings: false
        }
      })
    ]
  });
}