old_contents: var path = require('path');
  var webpack = require('webpack');
  var HTMLPlugin = require('html-webpack-plugin');
  
  module.exports = {
    resolve: {
      root: path.resolve('./src'),
      extensions: ['', '.js'],
      alias: { vue: 'vue/dist/vue.js' },
    },
    entry: [
      './src/main.js',
      'webpack/hot/dev-server',
      'webpack-hot-middleware/client',
    ],
    output: {
      path:  path.join(__dirname, 'dist'),
      publicPath: '/static/',
      filename: 'bundle.js'
    },
    module: {
      loaders: [
        { test: /\.js$/, exclude: /node_modules/, loader: 'babel-loader' },
        { test: /\.css$/, exclude: /node_modules/, loader: 'style-loader!css-loader' },
        { test: /\.vue/, exclude: /node_modules/, loader: 'vue-loader' },
      ],
      noParse: [new RegExp('node_modules/localforage/dist/localforage.js')]
    },
    plugins: [
      new webpack.HotModuleReplacementPlugin()
    ],
  };
  
new_contents: var path = require('path');
  var webpack = require('webpack');
  var HTMLPlugin = require('html-webpack-plugin');
  
  module.exports = {
    devtool: 'source-map',
    resolve: {
      root: path.resolve('./src'),
      extensions: ['', '.js'],
      alias: { vue: 'vue/dist/vue.js' },
    },
    entry: [
      './src/main.js',
      'webpack/hot/dev-server',
      'webpack-hot-middleware/client',
    ],
    output: {
      path:  path.join(__dirname, 'dist'),
      publicPath: '/static/',
      filename: 'bundle.js',
    },
    module: {
      loaders: [
        { test: /\.js$/, exclude: /node_modules/, loader: 'babel-loader' },
        { test: /\.css$/, exclude: /node_modules/, loader: 'style-loader!css-loader' },
        { test: /\.vue/, exclude: /node_modules/, loader: 'vue-loader' },
      ],
      noParse: [new RegExp('node_modules/localforage/dist/localforage.js')]
    },
    plugins: [
      new webpack.HotModuleReplacementPlugin()
    ],
  };
  
subject: Update webpack devtool sourcemap