Webpack Babel


webpack is a module bundler. Its main purpose is to bundle JavaScript files for usage in a browser, yet it is also capable of transforming, bundling, or packaging just about any resource or asset.

Webpack Four Core Concepts:

  • entry
  • output
  • loaders
  • plugins


html-webpack-plugin (自动生成HTML插件)

clean-webpack-plugin (自动清空某个目录的文件)

const HtmlWebpackPlugin = require('html-webpack-plugin');
const CleanWebpackPlugin = require('clean-webpack-plugin');
module.exports = {
plugins: [
new CleanWebpackPlugin(['dist']),
new HtmlWebpackPlugin({
title: 'Output Management!',
template: 'index.html', //模板文件
filename: 'c.html',//生成的html文件
inject: false |‘head’,//js在html文件的head标签里面
chunks: ['main', 'c'], //对应的entry 里面定义的chunks
minify: {
removeComments: true,//remove comments
collapseWhitespace: true //minify html,remove whitespace


Babel is a JavaScript compiler

Babel is a toolchain that is mainly used to convert ECMAScript 2015+ code into a backwards compatible version of JavaScript in current and older browsers or environments.

JS loader (将es6转变为普通js)

npm install --save-dev babel-loader babel-core
npm install babel-preset-env --save-dev


通常在项目跟目录下,名称一般为 .babelrc

bebel preset

Babel presets can act as sharable set of Babel plugins and/or config options.

Official Presets

@babel/preset-env for compiling ES2015+ syntax
@babel/preset-typescript for TypeScript
@babel/preset-react for React
@babel/preset-flow for Flow

Using a Preset

"presets": ["babel-preset-myPreset", "@babel/preset-env"]

Preset Ordering

Preset ordering is reversed (last to first).

"presets": ["a", "b", "c"]

Will run in the following order: c, b, then a.

Preset Options

Both plugins and presets can have options specified by wrapping the name and an options object in an array inside your config.

"presets": [
"presetA", // bare string
["presetA"], // wrapped in array
["presetA", {}] // 2nd argument is an empty options object
"loose": true,
"modules": false

Babel 竞争者 SWC-Speedy Web Compiler

通过 rust 实现的 bable,速度快,但兼容性及生态比Babel 差

项目启动时,加载 node_modules 下某个js 因为js语法报错

通常 webpack 在构建时,是不会让 node_modules 下的文件走 babel tranpile 的,如果让 node_modules 下的文件也都走 babel tranpile会慢很多, 所以业界有个潜在的约定,npm 包发布前需要先用 babel 转出一份 es5 的代码。

但是有些 npm 包不遵守这个约定,没有转成 es5 就发上去,但有些包只支持 es5 的语法,遇到 const、let、()=> 类似的语法,就抛错了。

umi3 配置node_module 下的 pdfjs-dist 文件走babel tranpile

export default defineConfig({
nodeModulesTransform: {
type: 'none',
exclude: ['pdfjs-dist']

nextjs 配置 babel

例如要加 styled-components 插件的 server-side rendering 支持 https://styled-components.com/docs/tooling#babel-plugin
注意:因为是nextjs 项目 要先定义好 "presets": ["next/babel"],

"presets": ["next/babel"],
"plugins": ["babel-plugin-styled-components"]


rules: [
test: /\.js$/,
//如果有react文件 test: /(\.jsx|\.js)$/,
exclude: path.resolve(__dirname, 'node_modules'),
include: path.resolve(__dirname, 'src'),
loader: "babel-loader"

新建 .babelrc 文件 (指定要转换的js版本)

"presets": ["env"]
//如果有react文件 "presets": ["react", "env"]


npm install --save-dev style-loader css-loader
npm install --save-dev postcss-loader autoprefixer


test: /\.css$/,
use: [
loader: 'style-loader',
loader: 'css-loader',
options: {
importLoaders: 1,//让css里面的@import 的文件也经过postcss 的处理
loader: 'postcss-loader'

新建postcss.config.js 文件

module.exports = {
plugins: [