Webpack 打包工具

1. webpack 概念

[文档地址](https://www.webpackjs.com/concepts/)

2. webpack 命令使用及相关工具包

1. webpack 安装和打包命令：
    $ npm i webpack --save-dev
    $ webpack [source] [destination]
    
2. webpack 热部署工具安装和使用命令：
    $ npm i webpack-dev-server --save-dev  //安装
    $ webpack-dev-derver --open --port [port] --contentBase [content] --hot
        --open //自动打开浏览器
        --port //指定端口号
        --contentBase //指定根目录
        --hot //打开热部署

3. webpack 需要的第三方包：
    $ npm i vue-loader vue-template-complier
    $ npm i babel-core babel-loader babel-plugin-transform-runtime
    $ npm i babel-preset-env babel-preset-stage-0

3. webpack 配置文件模板

//webpack.config.js:

const path = require('path');
const webpack = require('webpack');
const htmlWebpackPlugin = require('html-webpack-plugin');

module.exports = {
  entry: path.join(__dirname, './src/main.js'), //入口文件
  output: { //指定输出项
      path: path.join(__dirname, './dist'), //输出路径
      filename: 'bundle.js' //指定输出文件名
  },
  plugins: [
    new webpack.HotModuleReplacementPlugin(),   //配置热部署
    new htmlWebpackPlugin({
        template: path.join(__dirname, './src/index.html'), //指定模板文件路径
        filename: 'index.html'  //指定浏览器打开的文件名      
    })
  ],
  module: {
      rules: [
        { test: /.css$/, use: ['style-loader', 'css-loader'] },    //处理.css文件的loader
        { test: /.css$/, use: ['style-loader', 'css-loader', 'less-loader'] },  //处理.less文件的loader
        { test: /.css$/, use: ['style-loader', 'css-loader', 'sass-loader'] },   //处理.scss的loader
        { test: /.(jpg|png|gif|jpeg|bmp)$/, use: 'url-loader?limit=[limit]&name=[hash:num]-[name].[ext]' },    //处理图片的loader
        { test: /.(ttf|eot|svg|woff|woff2)$/, use: 'url-loader' },  //处理字体的loader
        { test: /.js$/, use: 'babel-loader', exclude: /node_modules/ },    //配置babel转换高级的ES语法
        { test: /.vue$/, use: 'vue-loader' },  //处理.vue文件的loader
      ]
  },
  resolve: {
      "alias": {
          "vue$": "vue/dist/vue.js"
      }
  }
};