道理
DLL文件又称为动态链接库文件,它一般作为应用顺序可实行代码的一部分,供应用顺序在运转时举行挪用。
在Webpack中,内置的DllPlugin与DllReferencePlugin插件能够经由过程运用DLL来大幅进步构建机能,以下是DLL机制流程图:
初始化项目
为了便于试验,我们经由过程运用create-react-app
建立项目并eject出webpack设置:
npx create-react-app react-dll-demo
cd react-dll-demo && npm run eject
因为默许设置隐蔽了编译信息,翻开webpackDevServer.config.js
,将quiet: true
改成false,再启动一下项目,找出我们须要的信息:
Version: webpack 4.28.3
Time: 6985ms
Built at: 2019-02-21 10:46:42
Asset Size Chunks Chunk Names
asset-manifest.json 232 bytes [emitted]
index.html 1.65 KiB [emitted]
static/js/0.chunk.js 4.21 MiB 0 [emitted]
static/js/bundle.js 30.9 KiB runtime~main [emitted] runtime~main
static/js/main.chunk.js 47.4 KiB main [emitted] main
static/media/logo.5d5d9eef.svg 2.61 KiB [emitted]
DLLPlugin
起首在package.json的scripts字段增加一条剧本:
{
"build:dll": "webpack --config config/webpack.dll.config.js --mode production"
}
然后建立设置文件:
// config/webpack.dll.config.js
const webpack = require('webpack');
const path = require('path');
module.exports = {
entry: {
react: ['react', 'react-dom']
},
output: {
filename: '[name].dll.js',
path: path.join(__dirname, '../public/dll'),
libraryTarget: 'var',
library: '_dll_[name]_[hash]'
},
plugins: [
new webpack.DllPlugin({
path: path.join(__dirname, '../public/dll', '[name].manifest.json'),
name: '_dll_[name]_[hash]'
})
]
};
实行npm run build:dll
,CLI应该会自动提醒你装置webpack-cli
,运转完成后能够看到以下文件:
public/dll
├── react.dll.js
└── react.manifest.json
DLLReferencePlugin
翻开config/webpack.config.js
,在根对象plugins字段中写入该插件:
{
plugins: [
// ...
new webpack.DllReferencePlugin({
manifest: require(path.join(
__dirname,
'../public/dll/react.manifest.json'
))
}),
]
}
末了一个步骤,在index.html我们先手动引入dll依靠:
...
<div id="root"></div>
<script src="/dll/react.dll.js"></script>
...
此时从新运转顺序,守候项目一般运转,再检查一下编译信息:
Version: webpack 4.28.3
Time: 4883ms
Built at: 2019-02-21 11:19:11
Asset Size Chunks Chunk Names
asset-manifest.json 232 bytes [emitted]
index.html 1.69 KiB [emitted]
static/js/0.chunk.js 1.82 MiB 0 [emitted]
static/js/bundle.js 30.9 KiB runtime~main [emitted] runtime~main
static/js/main.chunk.js 52.1 KiB main [emitted] main
static/media/logo.5d5d9eef.svg 2.61 KiB [emitted]
很显然的看到,在development形式下,构建时候降低了2s,打包大小降低了2.4M,置信将DLL运用到项目工程中,你能收获到更多的欣喜。
优化
以上顺序只是为了疾速入手与demo搭建,须要优化的处所另有许多,在此简朴的枚举几点,供人人参考。
自动注入编译文件到HTML
经由过程装置html-webpack-include-assets-plugin
插件,能够自动将响应文件注入到index.html中,就能够防止手动举行更改了:
// config/webpack.config.js
const HtmlIncludeAssetsPlugin = require('html-webpack-include-assets-plugin');
// ...
{
plugins: [
new HtmlIncludeAssetsPlugin({
assets: ['dll/react.dll.js'],
append: false // 在其他资本前增加
}),
]
}
DLL的缓存题目与自动加载
我们一般不会对html文件做缓存,每次发版本时采纳增量宣布,只需html的依靠文件名变了,则会从新去剖析静态资本列表。除此之外,还须要供应一个函数,自动去加载文件夹内的多进口dll文件,以下为中心代码:
config/dllHelper.js:
// config/dllHelper.js
const webpack = require('webpack');
const path = require('path');
const fs = require('fs');
const dllConfig = require('./webpack.dll.config');
// 依据entry天生DllReferencePlugin列表
function genDllReferences() {
return Object.keys(dllConfig.entry).map(
name =>
new webpack.DllReferencePlugin({
manifest: require(path.join(
__dirname,
'../public/dll',
`${name}.manifest.json`
))
})
);
}
// 天生dll文件的静态资本途径
function loadDllAssets() {
return fs
.readdirSync(path.resolve(__dirname, '../public/dll'))
.filter(filename => filename.match(/.dll.js$/))
.map(filename => `dll/${filename}`);
}
module.exports = {
loadDllAssets,
genDllReferences
};
config/webpack.dll.config.js:
//
{
...
output: {
filename: '[name].[hash:8].dll.js'
}
}
config/webpack.config.js:
const dllHelper = require('./dllHelper');
...
{
plugins: [
...dllHelper.genDllReferences(),
new HtmlIncludeAssetsPlugin({
assets: dllHelper.loadDllAssets(),
append: false
})
]
}
构建前清空文件夹
若DLLPlugiun的entry发生变化,则dll内的文件可能会越来越多,因而我们须要在构建dll前清空文件夹,在这里引荐这两个package:
- npm-run-all,在scripts可串行或并行实行script
- rimraf,nodejs删除文件利器
起首装置响应依靠:yarn add -D rimraf npm-run-all
,然后修正package.json:
scripts: {
"make:dll": "npm-run-all clear:dll build:dll",
"build:dll": "webpack --config config/webpack.dll.config.js --mode production",
"clear:dll": "rimraf public/dll",
}
以后在更改DLL时,一定要记得实行:npm run make:dll
。
其他
Demo堆栈地点:GitHub – vv13/react-dll-demo