text: /**
   * @author: @AngularClass
   */
  
  const helpers = require('./helpers');
  /**
   * Used to merge webpack configs
  */
  const webpackMerge = require('webpack-merge');
  /**
   * The settings that are common to prod and dev
  */
  const commonConfig = require('./webpack.common.js');
  
  /**
   * Webpack Plugins
   */
  const DefinePlugin = require('webpack/lib/DefinePlugin');
  const ExtractTextPlugin = require('extract-text-webpack-plugin');
  const HashedModuleIdsPlugin = require('webpack/lib/HashedModuleIdsPlugin')
  const IgnorePlugin = require('webpack/lib/IgnorePlugin');
  const LoaderOptionsPlugin = require('webpack/lib/LoaderOptionsPlugin');
  const NormalModuleReplacementPlugin = require('webpack/lib/NormalModuleReplacementPlugin');
  const ProvidePlugin = require('webpack/lib/ProvidePlugin');
  const ModuleConcatenationPlugin = require('webpack/lib/optimize/ModuleConcatenationPlugin');
  const UglifyJsPlugin = require('uglifyjs-webpack-plugin');
  const OptimizeJsPlugin = require('optimize-js-plugin');
  const AotPlugin = require('@ngtools/webpack').AotPlugin;
  
  /**
   * Webpack Constants
   */
  const ENV = process.env.NODE_ENV = process.env.ENV = 'production';
  const HOST = process.env.HOST || 'localhost';
  const PORT = process.env.PORT || 8080;
  const AOT = process.env.BUILD_AOT || helpers.hasNpmFlag('aot');
  const METADATA = {
    host: HOST,
    port: PORT,
    ENV: ENV,
    HMR: false,
    AOT: AOT
  };
  
  module.exports = function (env) {
    return webpackMerge(commonConfig({
      env: ENV
    }), {
  
      /**
       * Developer tool to enhance debugging
       *
       * See: http://webpack.github.io/docs/configuration.html#devtool
       * See: https://github.com/webpack/docs/wiki/build-performance#sourcemaps
       */
      devtool: 'source-map',
  
      /**
       * Options affecting the output of the compilation.
       *
       * See: http://webpack.github.io/docs/configuration.html#output
       */
      output: {
  
        /**
         * The output directory as absolute path (required).
         *
         * See: http://webpack.github.io/docs/configuration.html#output-path
         */
        path: helpers.root('dist'),
  
        /**
         * Specifies the name of each output file on disk.
         * IMPORTANT: You must not specify an absolute path here!
         *
         * See: http://webpack.github.io/docs/configuration.html#output-filename
         */
        filename: '[name].[chunkhash].bundle.js',
  
        /**
         * The filename of the SourceMaps for the JavaScript files.
         * They are inside the output.path directory.
         *
         * See: http://webpack.github.io/docs/configuration.html#output-sourcemapfilename
         */
        sourceMapFilename: '[file].map',
  
        /**
         * The filename of non-entry chunks as relative path
         * inside the output.path directory.
         *
         * See: http://webpack.github.io/docs/configuration.html#output-chunkfilename
         */
        chunkFilename: '[name].[chunkhash].chunk.js'
  
      },
  
      module: {
        loaders: [
          { test: /\.ts$/, loader: '@ngtools/webpack' }
        ], 
  
        rules: [
  
          /**
           * Extract CSS files from .src/styles directory to external CSS file
           */
          {
            test: /\.css$/,
            loader: ExtractTextPlugin.extract({
              fallback: 'style-loader',
              use: 'css-loader'
            }),
            include: [helpers.root('src', 'styles')]
          },
  
          /**
           * Extract and compile SCSS files from .src/styles directory to external CSS file
           */
          {
            test: /\.scss$/,
            loader: ExtractTextPlugin.extract({
              fallback: 'style-loader',
              use: 'css-loader!sass-loader'
            }),
            include: [helpers.root('src', 'styles')]
          },
  
        ]
  
      },
  
      /**
       * Add additional plugins to the compiler.
       *
       * See: http://webpack.github.io/docs/configuration.html#plugins
       */
      plugins: [
  
        new AotPlugin({
          tsConfigPath: './tsconfig.json',
          entryModule: 'src/app/app.module.ts#AppModule'
        }), 
  
        new ModuleConcatenationPlugin(),
  
        /**
         * Webpack plugin to optimize a JavaScript file for faster initial load
         * by wrapping eagerly-invoked functions.
         *
         * See: https://github.com/vigneshshanmugam/optimize-js-plugin
         */
        new OptimizeJsPlugin({
          sourceMap: false
        }),
  
        /**
         * Plugin: ExtractTextPlugin
         * Description: Extracts imported CSS files into external stylesheet
         *
         * See: https://github.com/webpack/extract-text-webpack-plugin
         */
        new ExtractTextPlugin('[name].[contenthash].css'),
  
        /**
         * Plugin: DefinePlugin
         * Description: Define free variables.
         * Useful for having development builds with debug logging or adding global constants.
         *
         * Environment helpers
         *
         * See: https://webpack.github.io/docs/list-of-plugins.html#defineplugin
         */
        // NOTE: when adding more properties make sure you include them in custom-typings.d.ts
        new DefinePlugin({
          'ENV': JSON.stringify(METADATA.ENV),
          'HMR': METADATA.HMR,
          'AOT': METADATA.AOT,
          'process.env.ENV': JSON.stringify(METADATA.ENV),
          'process.env.NODE_ENV': JSON.stringify(METADATA.ENV),
          'process.env.HMR': METADATA.HMR
        }),
  
        /**
         * Plugin: UglifyJsPlugin
         * Description: Minimize all JavaScript output of chunks.
         * Loaders are switched into minimizing mode.
         *
         * See: https://webpack.github.io/docs/list-of-plugins.html#uglifyjsplugin
         *
         * NOTE: To debug prod builds uncomment //debug lines and comment //prod lines
         */
        new UglifyJsPlugin({
          parallel: true,
          uglifyOptions: {
            ie8: false,
            ecma: 6,
            warnings: true,
            mangle: true, // debug false
            output: {
              comments: false,
              beautify: false,  // debug true
            }
          },
          warnings: true,
        }),
  
        /**
         * Plugin: NormalModuleReplacementPlugin
         * Description: Replace resources that matches resourceRegExp with newResource
         *
         * See: http://webpack.github.io/docs/list-of-plugins.html#normalmodulereplacementplugin
         */
        new NormalModuleReplacementPlugin(
          /(angular2|@angularclass)((\\|\/)|-)hmr/,
          helpers.root('config/empty.js')
        ),
  
        new NormalModuleReplacementPlugin(
          /zone\.js(\\|\/)dist(\\|\/)long-stack-trace-zone/,
          helpers.root('config/empty.js')
        ),
  
        new HashedModuleIdsPlugin(),
  
        /**
         * AoT
         * Manually remove compiler just to make sure it's gone
         */
        (AOT ? (
          new NormalModuleReplacementPlugin(
            /@angular(\\|\/)compiler/,
            helpers.root('config/empty.js')
          )
        ) : (new LoaderOptionsPlugin({}))),
  
        /**
         * Plugin: CompressionPlugin
         * Description: Prepares compressed versions of assets to serve
         * them with Content-Encoding
         *
         * See: https://github.com/webpack/compression-webpack-plugin
         */
        //  install compression-webpack-plugin
        // new CompressionPlugin({
        //   regExp: /\.css$|\.html$|\.js$|\.map$/,
        //   threshold: 2 * 1024
        // })
  
        /**
         * Plugin LoaderOptionsPlugin (experimental)
         *
         * See: https://gist.github.com/sokra/27b24881210b56bbaff7
         */
        new LoaderOptionsPlugin({
          minimize: true,
          debug: false,
          options: {
  
            /**
             * Html loader advanced options
             *
             * See: https://github.com/webpack/html-loader#advanced-options
             */
            // TODO: Need to workaround Angular 2's html syntax => #id [bind] (event) *ngFor
            htmlLoader: {
              minimize: true,
              removeAttributeQuotes: false,
              caseSensitive: true,
              customAttrSurround: [
                [/#/, /(?:)/],
                [/\*/, /(?:)/],
                [/\[?\(?/, /(?:)/]
              ],
              customAttrAssign: [/\)?\]?=/]
            },
  
          }
        }),
  
        /**
         * Plugin: BundleAnalyzerPlugin
         * Description: Webpack plugin and CLI utility that represents
         * bundle content as convenient interactive zoomable treemap
         *
         * `npm run build:prod -- --env.analyze` to use
         *
         * See: https://github.com/th0r/webpack-bundle-analyzer
         */
  
      ],
  
      /**
       * Include polyfills or mocks for various node stuff
       * Description: Node configuration
       *
       * See: https://webpack.github.io/docs/configuration.html#node
       */
      node: {
        global: true,
        crypto: 'empty',
        process: false,
        module: false,
        clearImmediate: false,
        setImmediate: false
      }
  
    });
  }
  