本文介绍了webpack中CommonsChunkPlugin详细教程(小结)，分享给大家，也给自己留个笔记，具体如下：
1.demo结构：
2.package.json配置：
{
"name": "webpack-simple-demo",
"version": "1.0.0",
"description": "",
"main": "index.js",
"scripts": {
"webpack": "webpack"
},
"author": "",
"license": "ISC",
"dependencies": {
"jquery": "^3.1.0",
"vue": "^1.0.26"
},
"devDependencies": {
"css-loader": "^0.24.0",
"style-loader": "^0.13.1",
"webpack": "^1.13.2",
"webpack-dev-server": "^1.15.1"
}
}
3.多种打包情况(未使用CommonsChunkPlugin)
(1)单一入口，模块单一引用
webpack.config.js
var CommonsChunkPlugin = require("webpack/lib/optimize/CommonsChunkPlugin");
module.exports = {
entry:
{
main:'./main.js',
},
output: {
path:__dirname+'/dist',
filename: 'build.js'
},
plugins: [
]
};
main.js
require("jquery");
demo目录下运行命令行 webpack或npm run webpack
jquery模块被一起打包到build.js
(2)单一入口，模块重复引用
webpack.config.js不变，main.js：
require("./chunk1");
require("./chunk2");
chunk1.js:
require("./chunk2");
var chunk1=1;
exports.chunk1=chunk1;
chunk2.js:
var chunk2=1; exports.chunk2=chunk2;
main.js引用了chunk1、chunk2,chunk1又引用了chunk2，打包后：
build.js:
...省略webpack生成代码
([
function(module, exports, __webpack_require__) {
__webpack_require__(1);
__webpack_require__(2);
},
function(module, exports, __webpack_require__) {
__webpack_require__(2);
var chunk1=1;
exports.chunk1=chunk1;
},
function(module, exports) {
var chunk2=1;
exports.chunk2=chunk2;
}
]);
(3)多入口，模块单一引用，分文件输出
webpack.config.js
var CommonsChunkPlugin = require("webpack/lib/optimize/CommonsChunkPlugin");
module.exports = {
entry:
{
main:'./main.js',
main1:'./main1.js'
},
output: {
path:__dirname+'/dist',
filename: '[name].js'
},
plugins: [
]
};
打包后文件main.js,main1.js 内容与（2）build.js一致
（4）多入口，模块单一引用，单一文件输出
var CommonsChunkPlugin = require("webpack/lib/optimize/CommonsChunkPlugin");
module.exports = {
entry:
{
main:'./main.js',
main1:'./main1.js'
},
output: {
path:__dirname+'/dist',
filename: 'buid.js'
},
plugins: [
]
};
build.js与（2）一致
（5）多入口，模块重复引用，单文件输出
webpack.config.js与（4）一致
main.js
require("./chunk1");
require("./chunk2");
exports.main=1;
main1.js
require("./chunk1");
require("./chunk2");
require("./main");
报错：ERROR in ./main1.js
Module not found: Error: a dependency to an entry point is not allowed
@ ./main1.js 3:0-17
4.使用CommonsChunkPlugin
(1)单一入口，模块单一引用，分文件输出:
webpack.config.js
var CommonsChunkPlugin = require("webpack/lib/optimize/CommonsChunkPlugin");
module.exports = {
entry:
{
main:'./main.js',
},
output: {
path:__dirname+'/dist',
filename: '[name].js'//不使用[name]，并且插件中没有filename，这输出文件中只用chunk.js的内容，
main.js的内容不知跑哪里去了
},
plugins: [
new CommonsChunkPlugin({
name:"chunk",
filename:"chunk.js"//忽略则以name为输出文件的名字，否则以此为输出文件名字
})
]
};
main.js
require("./chunk1");
require("./chunk2");
require("jquery");
输出文件main.js chunk.js,chunk1.js,chunck2.js,jquery都被打包到main.js里，好像并没有什么卵用，但是页面上使用的时候chunk.js必须在mian.js前引用
将chunk1.js,chunck2.js打包到chunk.js:
webpack.config.js
var CommonsChunkPlugin = require("webpack/lib/optimize/CommonsChunkPlugin");
module.exports = {
entry:
{
main:'./main.js',
chunk: ["./chunk1", "./chunk2"],//插件中name,filename必须以这个key为值
},
output: {
path:__dirname+'/dist',
filename: '[name].js'//不使用[name]，并且插件中没有filename，
这输出文件中只用chunk.js的内容，main.js的内容不知跑哪里去了
},
plugins: [
new CommonsChunkPlugin({
name:"chunk",
// filename:"chunk.js"//忽略则以name为输出文件的名字，否则以此为输出文件名字
})
]
};
(1)单一入口，模块重复引用，分文件输出(单一入口CommonsChunkPlugin能否将多次引用的模块打包到公共模块呢？)：
webpack.config.js
var CommonsChunkPlugin = require("webpack/lib/optimize/CommonsChunkPlugin");
module.exports = {
entry:
{
main:'./main.js',
//main1:'./main1.js',
},
output: {
path:__dirname+'/dist',
filename: '[name].js'//不使用[name]，并且插件中没有filename，
这输出文件中只用chunk.js的内容，main.js的内容不知跑哪里去了
},
plugins: [
new CommonsChunkPlugin({
name:"chunk",
// filename:"chunk.js"//忽略则以name为输出文件的名字，否则以此为输出文件名字
minChunks:2
})
]
};
main.js
require("./chunk1");
require("./chunk2");
chunk1.js
require("./chunk2");
var chunk1=1;
exports.chunk1=chunk1;
chunk2模块被引用了两次
打包后，所有模块还是被打包到main.js中
(3)多入口，模块重复引用，分文件输出（将多次引用的模块打包到公共模块）
webpack.config.js
var CommonsChunkPlugin = require("webpack/lib/optimize/CommonsChunkPlugin");
module.exports = {
entry:
{
main:'./main.js',
main1:'./main1.js',
},
output: {
path:__dirname+'/dist',
filename: '[name].js'//不使用[name]，并且插件中没有filename，
这输出文件中只用chunk.js的内容，main.js的内容不知跑哪里去了
},
plugins: [
new CommonsChunkPlugin({
name:"chunk",
// filename:"chunk.js"//忽略则以name为输出文件的名字，否则以此为输出文件名字
minChunks:2
})
]
};
main.js,main1.js里都引用chunk1,chunk2.
打包后：
chunk1,chunk2被打包到chunk.js,不再像3(3)chunk1,chunk2分别被打包到mian,mian1中。
5.将公共业务模块与类库或框架分开打包
webpack.config.js
var CommonsChunkPlugin = require("webpack/lib/optimize/CommonsChunkPlugin");
module.exports = {
entry: {
main: './main.js',
main1: './main1.js',
common1: ['jquery'],
common2: ['vue']
},
output: {
path: __dirname + '/dist',
filename: '[name].js'//不使用[name]，并且插件中没有filename，
//这输出文件中只用chunk.js的内容，main.js的内容不知跑哪里去了
},
plugins: [
new CommonsChunkPlugin({
name: ["chunk","common1","common2"],//页面上使用的时候common2
//必须最先加载
// filename:"chunk.js"//忽略则以name为输出文件的名字，
//否则以此为输出文件名字
minChunks: 2
})
]
};
jquery被打包到common1.js,vue被打包到common2.js,chunk.js打包的是公共的业务模块(webpack用插件CommonsChunkPlugin进行打包的时候，将符合引用次数(minChunks)的模块打包到name参数的数组的第一个块里（chunk）,然后数组后面的块依次打包(查找entry里的key,没有找到相关的key就生成一个空的块)，最后一个块包含webpack生成的在浏览器上使用各个块的加载代码，所以页面上使用的时候最后一个块必须最先加载)
将webpack.config.js改为
var CommonsChunkPlugin = require("webpack/lib/optimize/CommonsChunkPlugin");
module.exports = {
entry: {
main: './main.js',
main1: './main1.js',
jquery:["jquery"],
vue:["vue"]
},
output: {
path: __dirname + '/dist',
filename: '[name].js'
},
plugins: [
new CommonsChunkPlugin({
name: ["common","jquery","vue","load"],
minChunks:2
})
]
};
main.js
require("./chunk1");
require("./chunk2");
var jq=require("jquery");
console.log(jq);
main1.js
require("./chunk1");
require("./chunk2");
var vue=require("vue");
console.log(vue);
exports.vue=vue;
打包后
common.js
webpackJsonp([4,5],[
,
,
function(module, exports, __webpack_require__) {
__webpack_require__(3);
var chunk1=1;
exports.chunk1=chunk1;
},
function(module, exports) {
var chunk2=1;
exports.chunk2=chunk2;
}
]);
相当于公共的业务代码都打包到了common.js里
load.js
(function(modules) { // webpackBootstrap
// install a JSONP callback for chunk loading
var parentJsonpFunction = window["webpackJsonp"];
window["webpackJsonp"] = function webpackJsonpCallback(chunkIds, moreModules) {
// add "moreModules" to the modules object,
// then flag all "chunkIds" as loaded and fire callback
var moduleId, chunkId, i = 0, callbacks = [];
for(;i < chunkIds.length; i++) {
chunkId = chunkIds[i];
if(installedChunks[chunkId])
callbacks.push.apply(callbacks, installedChunks[chunkId]);
installedChunks[chunkId] = 0;
}
for(moduleId in moreModules) {
modules[moduleId] = moreModules[moduleId];
}
if(parentJsonpFunction) parentJsonpFunction(chunkIds, moreModules);
while(callbacks.length)
callbacks.shift().call(null, __webpack_require__);
if(moreModules[0]) {
installedModules[0] = 0;
return __webpack_require__(0);
}
};
// The module cache
var installedModules = {};
// object to store loaded and loading chunks
// "0" means "already loaded"
// Array means "loading", array contains callbacks
var installedChunks = {
5:0
};
// The require function
function __webpack_require__(moduleId) {
// Check if module is in cache
if(installedModules[moduleId])
return installedModules[moduleId].exports;
// Create a new module (and put it into the cache)
var module = installedModules[moduleId] = {
exports: {},
id: moduleId,
loaded: false
};
// Execute the module function
modules[moduleId].call(module.exports, module, module.exports, __webpack_require__);
// Flag the module as loaded
module.loaded = true;
// Return the exports of the module
return module.exports;
}
// This file contains only the entry chunk.
// The chunk loading function for additional chunks
__webpack_require__.e = function requireEnsure(chunkId, callback) {
// "0" is the signal for "already loaded"
if(installedChunks[chunkId] === 0)
return callback.call(null, __webpack_require__);
// an array means "currently loading".
if(installedChunks[chunkId] !== undefined) {
installedChunks[chunkId].push(callback);
} else {
// start chunk loading
installedChunks[chunkId] = [callback];
var head = document.getElementsByTagName('head')[0];
var script = document.createElement('script');
script.type = 'text/javascript';
script.charset = 'utf-8';
script.async = true;
script.src = __webpack_require__.p + "" + chunkId + "." + ({"0":"jquery","1":"main","2":"main1","3":"vue","4":"common"}[chunkId]||chunkId) + ".js";
head.appendChild(script);
}
};
// expose the modules object (__webpack_modules__)
__webpack_require__.m = modules;
// expose the module cache
__webpack_require__.c = installedModules;
// __webpack_public_path__
__webpack_require__.p = "";
})
([]);
使用的时候必须最先加载load.js
6.参数minChunks: Infinity
看一下下面的配置会是什么结果
var CommonsChunkPlugin = require("webpack/lib/optimize/CommonsChunkPlugin");
module.exports = {
entry: {
main: './main.js',
main1: './main1.js',
jquery:["jquery"]
},
output: {
path: __dirname + '/dist',
filename: '[name].js'
},
plugins: [
new CommonsChunkPlugin({
name: "jquery",
minChunks:2
})
]
};
main.js,main1.js共同引用的chunk1和chunk2会被打包到jquery.js里
minChunks:2修改为minChunks:Infinity后，chunk1和chunk2都打包到main.js,main1.js里
7.参数chunks
webpack.config.js
var CommonsChunkPlugin = require("webpack/lib/optimize/CommonsChunkPlugin");
module.exports = {
entry: {
main: './main.js',
main1: './main1.js',
jquery:["jquery"]
},
output: {
path: __dirname + '/dist',
filename: '[name].js'
},
plugins: [
new CommonsChunkPlugin({
name: "jquery",
minChunks:2,
chunks:["main","main1"]
})
]
};
只有在main.js和main1.js中都引用的模块才会被打包的到公共模块（这里即jquery.js）
以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持考高分网。
