Webpack：Tree Shaking（9）
介绍
Three Shaking只支持import的静态引入模块的模式，require是commonJS动态引入不支持。在production打包模式下自动被使用。
webpack.config.js
const path = require('path');
var HtmlWebpackPlugin = require('html-webpack-plugin');
const {
CleanWebpackPlugin } = require('clean-webpack-plugin');
const webpack = require('webpack');
module.exports = {
mode: 'development',
devtool: 'cheap-module-eval-source-map',
entry: {
main: './src/index.js'
},
module: {
rules: [
{
test: /\.js$/,
exclude: /node_modules/,
loader: "babel-loader"
}
]
},
devServer: {
contentBase: './dist'
},
plugins: [
new HtmlWebpackPlugin({
template: 'src/index.html'
}),
new CleanWebpackPlugin()
],
optimization: {
//development打包的模式才需要这个
usedExports: true
},
output: {
filename: '[name].js',
path: path.resolve(__dirname, 'dist')
}
};
pageck.json
配置文件的sideEffects字段，使css等配置文件不要被tree shaking掉。tree shaking会检查文件是否有导出，像css文件这种没有导出的都会被tree shaking掉。
{
"name": "webpack-demo",
"sideEffects": [
"*.css"
],
"version": "1.0.0",
"description": "",
"main": "webpack.config.js",
"dependencies": {
"@babel/polyfill": "^7.11.5",
"@babel/runtime-corejs2": "^7.11.2",
"url-loader": "^4.1.0",
"webpack": "^4.44.2",
"webpack-cli": "^3.3.12"
},
"devDependencies": {
"@babel/core": "^7.11.6",
"@babel/plugin-transform-runtime": "^7.11.5",
"@babel/preset-env": "^7.11.5",
"autoprefixer": "^9.8.6",
"babel-loader": "^8.1.0",
"clean-webpack-plugin": "^3.0.0",
"css-loader": "^4.3.0",
"file-loader": "^6.1.0",
"html-webpack-plugin": "^4.5.0",
"node-sass": "^4.14.1",
"postcss-loader": "^4.0.2",
"sass-loader": "^10.0.2",
"style-loader": "^1.2.1",
"webpack-dev-server": "^3.11.0"
},
"scripts": {
"watch": "webpack --watch",
"start": "webpack-dev-server --open",
"boundle": "webpack"
},
"keywords": [],
"author": "",
"license": "ISC",
"browserslist": [
"> 1%",
"last 2 versions",
"not ie <= 8"
]
}