webpack css兼容性处理踩坑记录

1、目录文件

2、全局配置需要的loader 和 plugins（已经安装webpack的前提下，全局安装 npm install webpack webpack-cli -D）

1. 全局安装 css-loader，指令：npm install css-loader -D
2. 全局安装 less-loader，指令：npm install less-loader -D
3. 全局安装 postcss-loader，指令：npm install postcss-loader -D
4. 全局安装 postcss-preset-env，指令：npm install postcss-preset-env -D
5. 全局安装 html-webpack-plugin 插件，指令：npm install html-webpack-plugin -D
6. 全局安装 mini-css-extract-plugin 插件，指令：npm install mini-css-extract-plugin -D

3、webpack.config.js配置

// 引入 node.js path 核心模块
const { resolve } = require('path');
const HtmlWebpackPlugin = require('html-webpack-plugin');
const MiniCssExtractPlugin = require('mini-css-extract-plugin');

// 设置 node.js 环境变量 => 默认是生产环境production
process.env.NODE_ENV = 'development'

module.exports = {
    mode: 'development',
    entry: './src/js/index.js',
    output: {
        filename: 'js/build.js',
        path: resolve(__dirname, 'build')
    },
    module: {
        rules: [
            {
                test: /\.css$/,
                use: [
                    MiniCssExtractPlugin.loader,
                    'css-loader',
                    /*
                        css 兼容性处理： postcss => postcss-loader postcss-preset-env
                        帮 postcss 找到 package.json 中 browserslist 里面的配置，通过配置加载指定的 css 兼容性样式
                        "browserslist": {
                            // 开发环境 
                            "development": [
                                "last 1 chrome version", => 最近的 chrome 浏览器版本
                                "last 1 firefox version", => 最近的 firefox 浏览器版本
                                "last 1 safari version" => 最近的 safari 浏览器版本
                            ],
                            // 生产环境：默认是生产环境，所有需要配置 node 环境变量
                            "production": [
                                ">0.2%", => 兼容98%以上的浏览器
                                "not dead", => 排除掉已经摒弃了的浏览器
                                "not op_mini all"
                            ]
                        }
                    */
                    {
                        loader: 'postcss-loader',
                        options: {
                            ident: 'postcss',
                            plugins: () => [
                                require('postcss-preset-env')()
                            ]
                        }
                    }
                ]
            },
            {
                test: /\.less$/,
                use: [
                    MiniCssExtractPlugin.loader,
                    'css-loader',
                    'less-loader'
                ]
            }
        ]
    },
    plugins: [
        new HtmlWebpackPlugin({
            template: './src/index.html'
        }),
        new MiniCssExtractPlugin({
            // 对输出的 css 文件重命名  => 默认的是 main.css
            filename: 'css/build.css'
        })
    ],
    devServer: {
        contentBase: resolve(__dirname, 'build'),
        port: 3000,
        open: true,
        compress: true,
    }
}

4、package.json配置

{
  "name": "index",
  "version": "1.0.0",
  "description": "",
  "main": "index.js",
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1"
  },
  "author": "",
  "license": "ISC",
  "devDependencies": {
    "css-loader": "^4.2.2",
    "html-webpack-plugin": "^4.4.1",
    "less": "^3.12.2",
    "less-loader": "^7.0.1",
    "mini-css-extract-plugin": "^0.11.0",
    "postcss-loader": "^4.0.0",
    "postcss-preset-env": "^6.7.0",
    "style-loader": "^1.2.1",
    "webpack": "^4.44.1",
    "webpack-cli": "^3.3.12",
    "webpack-dev-server": "^3.11.0"
  },
  "browserslist": {
    "development": [
      "last 1 chrome version",
      "last 1 firefox version",
      "last 1 safari version"
    ],
    "production": [
      ">0.2%",
      "not dead",
      "not op_mini all"
    ]
  }
}

5、完成配置，使用webpack打包会出现以下报错

解决：postcss-loader下的options下的配置应该写在postcssOptions对象中

错误代码实例

正确代码实例