old_contents: var webpack = require('webpack');
  var path = require('path');
  
  var APP_DIR = path.join(__dirname, '..', 'app');
  
  module.exports = {
    debug: true,
    devtool: 'eval',
    entry: ['webpack-hot-middleware/client', './app/index.tsx'],
    module: {
      preLoaders: [{
        test: /\.tsx?$/,
        loader: 'tslint',
        include: APP_DIR
      }],
      loaders: [{
        test: /\.tsx?$/,
        loaders: ['babel', 'awesome-typescript-loader'],
        include: APP_DIR
      }]
    },
    output: {
      filename: 'app.js',
      path: path.join(__dirname, '..', 'build'),
      publicPath: '/static/'
    },
    plugins: [
      new webpack.optimize.OccurrenceOrderPlugin(),
      new webpack.HotModuleReplacementPlugin(),
      new webpack.NoErrorsPlugin()
    ],
    resolve: {
      root: [path.resolve('../app')],
      extensions: ['', '.jsx', '.js', '.tsx', '.ts']
    }
  };
  
new_contents: var webpack = require('webpack');
  var path = require('path');
  
  var APP_DIR = path.join(__dirname, '..', 'app');
  
  module.exports = {
    debug: true,
    devtool: 'eval',
    entry: ['webpack-hot-middleware/client', './app/index.tsx'],
    module: {
      preLoaders: [{
        test: /\.tsx?$/,
        loader: 'tslint',
        include: APP_DIR
      }],
      loaders: [{
        test: /\.tsx?$/,
        loaders: ['babel', 'awesome-typescript-loader'],
        include: APP_DIR
      }]
    },
    output: {
      filename: 'app.js',
      path: path.join(__dirname, '..', 'build'),
      publicPath: '/static/'
    },
    plugins: [
      new webpack.HotModuleReplacementPlugin(),
      new webpack.NoErrorsPlugin()
    ],
    resolve: {
      root: [path.resolve('../app')],
      extensions: ['', '.jsx', '.js', '.tsx', '.ts']
    }
  };
  
subject: Remove unnecessary optimization in dev.