webpack进阶之插件篇

摘要：基本环境搭建就不展开讲了一插件篇自动补全前缀官方是这样说的，也就是说它是一个自动检测兼容性给各个浏览器加个内核前缀的插件。

上一篇博客讲解了webpack环境的基本，这一篇讲解一些更深入的内容和开发技巧。基本环境搭建就不展开讲了

autoprefixer

官方是这样说的：Parse CSS and add vendor prefixes to CSS rules using values from the Can I Use website
，也就是说它是一个自动检测兼容性给各个浏览器加个内核前缀的插件。

举个栗子：最新的弹性盒模型flux
实际代码：

:fullscreen a {
    display: flex
}

插件自动补充后

a {
    display: -webkit-box;
    display: -webkit-flex;
    display: -ms-flexbox;
    display: flex
}

效果显而易见，我们可以更专注于css布局和美化，而不需要花过多的精力都写相同的外码而加上不同的前缀，也减少了冗余代码。

使用方法:

cnpm install --save-dev autoprefixer postcss-loader

var autoprefixer = require("autoprefixer");
module.exports={
  //其他配置这里就不写了

  module:{
    loaders:[
    {
      test:/.css$/,
      //在原有基础上加上一个postcss的loader就可以了
      loaders:["style-loader","css-loader","postcss-loader"]
      }
      ]
  },
  postcss:[autoprefixer({browsers:["last 2 versions"]})]

}

html-webpack-plugin

cnpm install html-webpack-plugin --save-dev

  //webpack.config.js
  var HtmlWebpackPlugin = require("html-webpack-plugin");
  module.exports={
    entry:"./index.js",
    output:{
      path:__dirname+"/dist",
      filename:"bundle.js"
    }
    plugins:[
      new HtmlWebpackPlugin()
    ]
  }

作用:它会在dist目录下自动生成一个index.html

其他配置参数:

{
  entry: "index.js",
  output: {
    path: "dist",
    filename: "bundle.js"
  },
  plugins: [
    new HtmlWebpackPlugin({
      title: "My App",
      filename: "admin.html",
      template:"header.html",
      inject: "body",
      favicon:"./images/favico.ico",
      minify:true,
      hash:true,
      cache:false,
      showErrors:false,
      "chunks": {
      "head": {
        "entry": "assets/head_bundle.js",
        "css": [ "main.css" ]
      },
      xhtml:false
    })
  ]
}

--- header.html ---


  
    
    
  
  
  

作用：

  title: 设置title的名字   
  filename: 设置这个html的文件名   
  template:要使用的模块的路径  
  inject: 把模板注入到哪个标签后 "body",   
  favicon: 给html添加一个favicon  "./images/favico.ico",   
  minify:是否压缩  {...} | false （最新api变动，原来是ture|false 感谢@onmi指正)
  hash:是否hash化 true false ,     
  cache:是否缓存,   
  showErrors:是否显示错误,  
  chunks:目前没太明白  
  xhtml:是否自动毕业标签 默认false  

extract-text-webpack-plugin

官网是这么解释的Extract text from bundle into a file.,把额外的数据加到编译好的文件中

var ExtractTextPlugin = require("extract-text-webpack-plugin");
module.exports = {
    module: {
        loaders: [
            { test: /.css$/, loader: ExtractTextPlugin.extract("style-loader", "css-loader") }
        ]
    },
    plugins: [
        new HtmlWebpackPlugin({
                template: "./src/public/index.html",
                inject: "body"
            }),
        new ExtractTextPlugin("[name].[hash].css")
    ]
}

说明：将css放到index.html的body上面

copy-webpack-plugin

官方这样解释 Copy files and directories in webpack,在webpack中拷贝文件和文件夹

cnpm install --save-dev copy-webpack-plugin

new CopyWebpackPlugin([{
    from: __dirname + "/src/public"
}]),

作用：把public 里面的内容全部拷贝到编译目录

webpack.ProvidePlugin [webpack内置插件 ]

new webpack.ProvidePlugin({
    $: "jquery",
    jQuery: "jquery",
    "window.jQuery": "jquery"
}))
new webpack.NoErrorsPlugin(),
new webpack.optimize.DedupePlugin(),
new webpack.optimize.UglifyJsPlugin(),
new webpack.optimize.CommonsChunkPlugin("common.js")

作用: 和上面5个一一对应

  当模块使用这些变量的时候,wepback会自动加载。（区别于window挂载，感谢@lihuanghe121指正）
  不显示错误插件
  查找相等或近似的模块，避免在最终生成的文件中出现重复的模块
  丑化js 混淆代码而用
  提取公共代码的插件

"use strict";

// Modules
var webpack = require("webpack");
var autoprefixer = require("autoprefixer");
var HtmlWebpackPlugin = require("html-webpack-plugin");
var ExtractTextPlugin = require("extract-text-webpack-plugin");
var CopyWebpackPlugin = require("copy-webpack-plugin");

/**
 * Env
 * Get npm lifecycle event to identify the environment
 */
var ENV = process.env.npm_lifecycle_event;
var isTest = ENV === "test" || ENV === "test-watch";
var isProd = ENV === "build";

module.exports = function makeWebpackConfig() {
    var config = {};

    config.entry = isTest ? {} : {
        app: "./src/app/app.js"
    };

    config.output = isTest ? {} : {
        // Absolute output directory
        path: __dirname + "/dist",

        publicPath: isProd ? "/" : "http://localhost:8080/",

        filename: isProd ? "[name].[hash].js" : "[name].bundle.js",

        chunkFilename: isProd ? "[name].[hash].js" : "[name].bundle.js"
    };

    if (isTest) {
        config.devtool = "inline-source-map";
    } else if (isProd) {
        config.devtool = "source-map";
    } else {
        config.devtool = "eval-source-map";
    }

    config.module = {
        preLoaders: [],
        loaders: [{
            test: /.js$/,
            loader: "babel",
            exclude: /node_modules/
        }, {
            test: /.css/,
            loader: isTest ? "null" : ExtractTextPlugin.extract("style", "css?sourceMap!postcss")
        }, {
            test: /.(png|jpg|jpeg|gif|svg|woff|woff2|ttf|eot)$/,
            loader: "file"
        }, {
            test: /.json$/,
            loader: "json"
        }, {
            test: /.scss/,
            loader: "style!css!sass"
        }, {
            test: /.html$/,
            loader: "raw"
        }]
    };
    if (isTest) {
        config.module.preLoaders.push({
            test: /.js$/,
            exclude: [
                /node_modules/,
                /.spec.js$/
            ],
            loader: "isparta-instrumenter"
        })
    }

    config.postcss = [
        autoprefixer({
            browsers: ["last 2 version"]
        })
    ];

    config.plugins = [];
    if (!isTest) {
        config.plugins.push(
            new HtmlWebpackPlugin({
                template: "./src/public/index.html",
                inject: "body"
            }),

            new ExtractTextPlugin("[name].[hash].css", {disable: !isProd})
        )
    }

    if (isProd) {
        config.plugins.push(
            new webpack.NoErrorsPlugin(),

            new webpack.optimize.DedupePlugin(),

            new webpack.optimize.UglifyJsPlugin(),

            new CopyWebpackPlugin([{
                from: __dirname + "/src/public"
            }]),
            new webpack.ProvidePlugin({
                $: "jquery",
                jQuery: "jquery",
                "window.jQuery": "jquery"
            }))
    }

    config.devServer = {
        contentBase: "./src/public",
        stats: "minimal"
    };

    return config;
}();

if (isTest) {
    config.devtool = "inline-source-map";
} 

作用: 使用source-map可以在debug的时候看到源代码，方便 查错