TypeScript compilation extremely slow > 12s
<p>Just putting this out there to see if someone else is having this issue...</p>

<p>I have building an angular 2 app with typescript using webpack as my build tool, it all works well, however I have noticed typescript compilation is super super slow, I am at 12 seconds right now...., and its pretty clear that is all due to the typescript compilation process....</p>

<p>I have used ts-loader or awesome-typescript-loader with a similar result, if I comment out this loader, my build time drops to around 1 sec....</p>

<p>After some research it seems like its 'normal' to have 'slow' times when compiling typescript, but is 12secs the normal?? </p>

<p>Old posts hinted it might be due to a node version conflict, I am currently running v4.4.2...</p>

<p>Any how below is my webpack code in case anyone spots something wrong there.. the commented code in the Uglify section is due to some 'bug' on the angular 2 side...</p>

<pre><code>const path = require('path');
const merge = require('webpack-merge');
const webpack = require('webpack');

const NpmInstallPlugin = require('npm-install-webpack-plugin');
const CopyWebpackPlugin = require('copy-webpack-plugin');
const HtmlWebpackPlugin = require('html-webpack-plugin');
const TARGET = process.env.npm_lifecycle_event;

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

const common = {
  entry: {
    vendor: ['./app/vendor.ts'],
    main: ['./app/boot.component.ts']
  },
  output: {
    filename: '[name].[hash].bundle.js',
    path: PATHS.dist
  },
  resolve: {
    extensions: ['', '.js', '.ts']
  },
  plugins: [
    new HtmlWebpackPlugin({
      title: 'Qarrot Performance',
      template: 'index.template.ejs',
      commonStyles: [
        '/public/styles/vendor/normalize.css',
        '/public/styles/main.css'
      ],
      commonScripts: [],
      baseHref: '/',
      unsupportedBrowser: true,
      mobile: true,
      appMountId: 'app'
    }),
  ],
  module: {
    loaders: [
      {
        test: /\.ts$/,
        exclude: /node_modules/,
        loaders: ['ts-loader']
      },
      {
        test: /\.scss$/,
        loader: 'raw-loader!sass-loader'
      },
      {
        test: /\.html$/,
        loader: "html"
      }
    ]
  }
}

// Dev Settings
if(TARGET === 'start' || !TARGET) {
  module.exports = merge(common, {
    devtool: 'eval-source-map',
    devServer: {
      contentBase: PATHS.build,
      historyApiFallback: true,
      hot: true,
      inline: true,
      progress: true,
      stats: 'errors-only',
    },
    plugins: [
      new webpack.HotModuleReplacementPlugin(),
      new NpmInstallPlugin({
        save: true
      })
    ]
  });
}

// Prod Settings
if(TARGET === 'build') {
  module.exports = merge(common, {
    devtool: 'cheap-module-source-map',
    plugins: [
      // new webpack.optimize.UglifyJsPlugin({
      //   beautify: false,
      //   mangle: false,
      //   compress : { screw_ie8 : true },
      //   comments: false
      // }),
      new webpack.optimize.DedupePlugin(),
      new webpack.DefinePlugin({
        'process.env.NODE_ENV': '"production"'
      }),
      new CopyWebpackPlugin([
            { from: 'public', to: 'public' }
      ]),
      new webpack.optimize.CommonsChunkPlugin({
        names: ['vendor', 'manifest']
      }),
    ]
  });
}
</code></pre>

<p>I am also on a Mac, running Angular 2 beta.15 and webpack version 1.12, below is my tsconfig.json</p>

<pre><code>{
  "compilerOptions": {
    "target": "es5",
    "module": "commonjs",
    "moduleResolution": "node",
    "sourceMap": false,
    "emitDecoratorMetadata": true,
    "experimentalDecorators": true,
    "removeComments": false,
    "noImplicitAny": false
  },
  "compileOnSave": false,
  "exclude": [
    "node_modules",
    "typings/main",
    "typings/main.d.ts"
  ]
}
</code></pre>