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众所周知，一些新的css属性都会有一些浏览器的兼容问题，因此不同的浏览器都会给对应的css属性添加浏览器前缀。

此时我们需要引入postcss-loader和postcss-preset-env来处理这个情况。

npm i postcss-loader postcss-preset-env -D

webpack.config.js的配置如下：

const { resolve } = require('path');
const HtmlWebpackPlugin = require('html-webpack-plugin');
const miniCssExtractPlugin = require('mini-css-extract-plugin');
module.exports = {
    entry: './src/main.js',
    output: {
        filename: 'bundle.js',
        path: resolve(__dirname, 'dist')
    },
    module: {
        rules: [
            {
                test: /\.css$/,
                use: [miniCssExtractPlugin.loader, 'css-loader', 'postcss-loader']
            },
            {
                test: /\.less$/,
                use: [miniCssExtractPlugin.loader, 'css-loader', 'postcss-loader', 'less-loader']
            },
            {
                test: /\.scss$/,
                use: [miniCssExtractPlugin.loader, 'css-loader', 'postcss-loader', 'sass-loader']
            }
        ]
    },
    plugins: [
        new HtmlWebpackPlugin({
            template: './src/assets/index.html',
            hash: true,
            filename: 'index.html',
            favicon: './src/assets/favicon.ico'
        }),
        new miniCssExtractPlugin({
            filename: 'index.css'
        })
    ],
    mode: 'development'
}

使用postcss-preset-env需要新建一个配置文件postcss.config.js。

postcss.config.js的配置如下：

module.exports = {
    plugins: [
        require('postcss-preset-env')()
    ]
}

使用postcss-loader的时候就会默认调用postcss.config.js，postcss.config.js里引入了postcss-preset-env。此时postcss-preset-env并不知道怎么处理浏览器兼容，因此，我们需要在package.json中配置browserslist来告诉postcss-preset-env如何处理兼容。

package.json的配置如下：

{
  "name": "wpk5-demo",
  "version": "1.0.0",
  "description": "",
  "main": "index.js",
  "scripts": {
    "build": "npx webpack"
  },
  "keywords": [],
  "author": "",
  "license": "ISC",
  "devDependencies": {
    "css-loader": "^5.2.0",
    "html-webpack-plugin": "^5.3.1",
    "less": "^4.1.1",
    "less-loader": "^8.0.0",
    "mini-css-extract-plugin": "^1.4.0",
    "node-sass": "^5.0.0",
    "postcss-loader": "^5.2.0",
    "postcss-preset-env": "^6.7.0",
    "sass-loader": "^11.0.1",
    "style-loader": "^2.0.0",
    "webpack": "^5.28.0",
    "webpack-cli": "^4.5.0"
  },
  "browserslist": [
    "> 1%",
    "last 2 versions",
    "not ie <= 8"
  ]
}

git仓库地址：

https://gitee.com/seimin/xiaoming2qianduan-webpack5/tree/v5.4/