webpack css文件编译、自动添加前缀、剥离

1.css文件编译

webpack默认只能编译js文件，引入css需要loader支持

// css文件写入js中
npm i style-loader -D
// css文件loader
npm i css-loader -D

webpack.config.js的rules中添加

{
    test: /\.css$/,
    use:['style-loader', 'css-loader']
}

2.css自动添加前缀

// postcss-loader 可以给css自动添加-webkit -ms前缀
npm i postcss-loader -D

//autoprefixer插件，针对浏览器兼容设置
npm i autoprefixer -D

// 增加postcss-loader的option
新增文件postcss.config.js,内容：
module.exports = {
    plugins: {
        autoprefixer: {
            browsers: ['last 7 iOS versions', 'last 3 versions', '> 1%']
        }
    }
}

3.css剥离

//安装剥离插件（如果你是全局webpack,使用时会要你安装到当前项目）
npm i mini-css-extract-plugin -D

webpack.config.js中引入并使用

//引入
const MiniCssExtractPlugin = require("mini-css-extract-plugin");
//添加到plugins数组中
plugins:[
    new MiniCssExtractPlugin({
        filename: "css/main.css",
    })
]
//在rules中写入处理loader(之前的style-loader拿掉，因为不需要写入js文件了)
rules:[
    {
        test: /\.css$/,
        use:[MiniCssExtractPlugin.loader, 'css-loader', 'postcss-loader']
    }
]

package.json文件：

{
  "name": "csschange",
  "version": "1.0.0",
  "description": "",
  "main": "main.js",
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1",
    "build": "webpack --config webpack.config.js"
  },
  "keywords": [],
  "author": "",
  "license": "ISC",
  "devDependencies": {
    "autoprefixer": "^9.6.1",
    "css-loader": "^3.2.0",
    "mini-css-extract-plugin": "^0.8.0",
    "postcss-loader": "^3.0.0",
    "style-loader": "^1.0.0",
    "webpack": "^4.41.0",
    "webpack-cli": "^3.3.9"
  }
}

webpack.config.js文件：

const path = require('path')
const MiniCssExtractPlugin = require("mini-css-extract-plugin");
module.exports = {
    entry:'./main.js',
    output:{
        filename:'bundle.js',
        path:path.resolve(__dirname,'./dist')
    },
    module:{
        rules:[
            {
                test: /\.css$/,
                use:[MiniCssExtractPlugin.loader, 'css-loader', 'postcss-loader']
            }
        ]
    },
    plugins:[
        new MiniCssExtractPlugin({
            filename: "css/main.css",
        })
    ]
}

postcss.config.js文件：

module.exports = {
    plugins: {
        autoprefixer: {
            browsers: ['last 7 iOS versions', 'last 3 versions', '> 1%']
        }
    }
}