webpack-提取css单独文件和css兼容性

提取css单独文件

下载插件 npm install --save-dev mini-css-extract-plugin

配置文件:webpack.config.js

const HtmlWebpackPlugin = require('html-webpack-plugin')
const MiniCssExtractPlugin = require('mini-css-extract-plugin')
const {
    
     resolve }=require('path')
module.exports={
    
    
    entry:'./src/js/main.js',
    output:{
    
    
        filename:'js/built.js',
        path:resolve(__dirname,'build')
    },
    module:{
    
    
        //创建style标签，将样式放入style-loader
        //将css文件整合到js文件中
        rules:[{
    
    test:/\.css$/,use:[MiniCssExtractPlugin.loader,'css-loader']}]
    },
    plugins:[
        new HtmlWebpackPlugin({
    
    
            template:'./src/index.html'
        }),
        new MiniCssExtractPlugin({
    
    
            filename:'css/built.css', 
        })
    ],
    mode:'development'
}

主要添加了下面2个

const MiniCssExtractPlugin = require('mini-css-extract-plugin')

  new MiniCssExtractPlugin({
    
    
            filename:'css/built.css', 
        })

l.css

#box2{
    
    
    width: 100px;
    height: 100px;
    background-color: red;
}

t.css

#box1{
    
    
    width: 100px;
    height: 100px;
    background-color: blanchedalmond;
}

运行 webpack

生成一个built.css,将l.css和t.css内容整合在一起

css兼容性

下载 loader ： npm install --save-dev postcss-loader postcss-preset-env
配置文件：

const {
    
     resolve } = require('path');
const HtmlWebpackPlugin = require('html-webpack-plugin');
const MiniCssExtractPlugin = require('mini-css-extract-plugin');

// 设置nodejs环境变量
// process.env.NODE_ENV = 'development';

module.exports = {
    
    
  entry: './src/js/index.js',
  output: {
    
    
    filename: 'js/built.js',
    path: resolve(__dirname, 'build')
  },
  module: {
    
    
    rules: [
      {
    
    
        test: /\.css$/,
        use: [
          MiniCssExtractPlugin.loader,
          'css-loader',
          /*
            css兼容性处理：postcss --> postcss-loader postcss-preset-env

            帮postcss找到package.json中browserslist里面的配置，通过配置加载指定的css兼容性样式

            "browserslist": {
              // 开发环境 --> 设置node环境变量：process.env.NODE_ENV = development
              "development": [
                "last 1 chrome version",
                "last 1 firefox version",
                "last 1 safari version"
              ],
              // 生产环境：默认是看生产环境
              "production": [
                ">0.2%",
                "not dead",
                "not op_mini all"
              ]
            }
          */
          // 使用loader的默认配置
          // 'postcss-loader',
          // 修改loader的配置
          {
    
    
            loader: 'postcss-loader',
            options: {
    
    
              ident: 'postcss',
              plugins: () => [
                // postcss的插件
                require('postcss-preset-env')()
              ]
            }
          }
        ]
      }
    ]
  },
  plugins: [
    new HtmlWebpackPlugin({
    
    
      template: './src/index.html'
    }),
    new MiniCssExtractPlugin({
    
    
      filename: 'css/built.css'
    })
  ],
  mode: 'development'
};

package.json

  "browserslist": {
    
    
    "development": [
      "last 1 chrome version",  //适应最新的版本
      "last 1 firefox version",
      "last 1 safari version"
    ],
    "production": [
      ">0.2%",
      "not dead",
      "not op_mini all"
    ]
  }

最后运行webpack