// use npm 
npm install extract-text-webpack-plugin --save-dev

// or use yarn 
yarn add extract-text-webpack-plugin

var Ex = require('extract-text-webpack-plugin');
// ...省略
module: {
 loaders: [{
  test: /\.less/,
  loader: Ex.extract('style-loader', 'css-loader','less-loader') // 单独打包出CSS，这里配置注意下
 }]
},
plugins: [
 new Ex("【name】.css")
]

// webpack 1.x 配置  【早期使用的配置，那时候是1.x】
/*  webpack.config.js  */
var precss = require('precss');
var cssnext = require('cssnext');
var autoprefixer = require('autoprefixer');
var cssnano = require('cssnano');
var Ex = require('extract-text-webpack-plugin');
module.exports = {
  entry: './index.js',
  output: {
   filename: 'index.js'
  },
  module: {
   loaders: [{
    test: /\.less/,
    loader: Ex.extract('style-loader', 'css-loader','less-loader') // 单独打包出CSS，这里配置注意下
   }]
  },
  plugins: [
   new Ex("【name】.css")
  ]
 }

// webpack 3.x 的配置
var path = require('path')
var glob = require('globby') 
var webpack = require('webpack')
var ExtractTextPlugin = require('extract-text-webpack-plugin')

// CSS入口配置
var CSS_PATH = {
 css: {
  pattern: ['./src/**/[^_]*.less', '!./src/old/**/*.less'],
  src: path.join(__dirname, 'src'),
  dst: path.resolve(__dirname, 'static/build/webpack'),
 }
}

// 遍历除所有需要打包的CSS文件路径
function getCSSEntries(config) {
 var fileList = glob.sync(config.pattern)
 return fileList.reduce(function (previous, current) {
  var filePath = path.parse(path.relative(config.src, current))
  var withoutSuffix = path.join(filePath.dir, filePath.name)
  previous[withoutSuffix] = path.resolve(__dirname, current)
  return previous
 }, {})
}

module.exports = [
 {
  devtool: 'cheap-module-eval-source-map',
  context: path.resolve(__dirname),
  entry: getCSSEntries(CSS_PATH.css),
  output: {
   path: CSS_PATH.css.dst,
   filename: '[name].css'
  },
  module: {
   rules: [
    {
     test: /\.less$/,
     use: ExtractTextPlugin.extract({
      use: ['css-loader', 'postcss-loader', 'less-loader']
     })
    }
   ]
  },
  resolve: {
   extensions: ['.less']
  },
  plugins: [
   new ExtractTextPlugin('[name].css'),
  ]
 },
// 如果还需要打包js，则可以在这里增加一个单独打包js的处理【根据自己需求来】
// {
//  entry:{},
//  output:{},
//  ... 省略
// }
]

// webpack 1.x 版本
// ...其他配置和webpack3.x一样
module: {
  loaders: [
    {
      test: /\.less$/,
      loader: ExtractTextPlugin.extract("style-loader","css-loader","postcss-loader","less-loader")
    },
  ]
}
plugins: [
 new ExtractTextPlugin('[name].css'),
]
// ...其他配置和webpack3.x一样