webpack插件HtmlWebpackPlugin问题

Question

项目工程是使用generator-react-webpack生成的，在dev.js中使用htmlWebpackPlugin生成html。
其配置文件为：

'use strict';

let path = require('path');
let webpack = require('webpack');
let baseConfig = require('./base');
let defaultSettings = require('./defaults');

// Add needed plugins here
let BowerWebpackPlugin = require('bower-webpack-plugin');
let HtmlWebpackPlugin = require('html-webpack-plugin');

let config = Object.assign({}, baseConfig, {
  // entry: [
  //   'webpack-dev-server/client?http://127.0.0.1:' + defaultSettings.port,
  //   'webpack/hot/only-dev-server',
  //   './src/index'
  // ],
  entry: {
    app: path.join(__dirname, '../src/index.js')
  },
  cache: true,
  devtool: 'eval-source-map',
  plugins: [
    new HtmlWebpackPlugin({
      title: 'test',
      template: defaultSettings.srcPath + '/index.html',
      chunks: ['app'],
      filename: 'index.html'
    }),
    new webpack.HotModuleReplacementPlugin({
      multiStep: true
    }),
    new webpack.NoErrorsPlugin(),
    new BowerWebpackPlugin({
      searchResolveModulesDirectories: false
    })
  ],
  module: defaultSettings.getDefaultModules()
});

// Add needed loaders to the defaults here
config.module.loaders.push({
  test: /\.(js|jsx)$/,
  loader: 'babel-loader',
  include: [].concat(
    config.additionalPaths,
    [ path.join(__dirname, '/../src') ]
  )
},{
  test: /\.css$/,
  loader: 'style-loader!css-loader'
},
{
  test: /\.sass/,
  loader: 'style-loader!css-loader!sass-loader?outputStyle=expanded&indentedSyntax'
},
{
  test: /\.scss/,
  loader: 'style-loader!css-loader!sass-loader?outputStyle=expanded'
},
{
  test: /\.less/,
  loader: 'style-loader!css-loader!less-loader'
},
{
  test: /\.styl/,
  loader: 'style-loader!css-loader!stylus-loader'
});

module.exports = config;

在dist环境下可以正确的输出，模版变量也可以渲染。但是在dev环境下变量未渲染，html中也未引入js文件。
请问这个是怎么回事啊？