webpack4从0开始构建前端单页项目(12)用postcss-loader处理css

PostCSS这个插件就有点类似js的babel,babel是用来处理js的一些特性和兼容性的。PostCSS就是用来处理css的一些特性和兼容性的。比如补齐css的前缀等，支持一些css特性语法等。

安装 postcss-loader

    cnpm i postcss-loader -D

项目结构

    project
    |   .babelrc            # babel-loader配置文件
    |   .editorconfig       # 配置格式化插件
    |   package.json        # 项目需要的依赖
    |   webpack.config.js   # webpack配置文件
    |   postcss.config.js   # postcss配置文件
    |
    +---public
    |       index.html      # 用于打包生成 .html 文件的模板
    |
    ---src
            main.js         # webpack的入口文件
            style.sass       # sass文件

依赖的模块(package.json)

    "devDependencies": {
        "@babel/core": "^7.11.6",
        "@babel/preset-env": "^7.11.5",
        "babel-loader": "^8.1.0",
        "css-loader": "^4.3.0",
        "html-webpack-plugin": "^4.5.0",
        "mini-css-extract-plugin": "^0.11.3",
        "postcss-loader": "^4.0.3",
        "webpack": "^4.44.2",
        "webpack-cli": "^3.3.12",
        "webpack-dev-server": "^3.11.0"
    },

webpack 配置文件

// webpack.config.js
    const webpack = require("webpack");
    const path = require("path");
    const htmlWebpackPlugin = require("html-webpack-plugin");
    const MiniCssExtractPlugin = require("mini-css-extract-plugin");

    module.exports = {
        entry: "./src/main.js",
        mode: "development",
        output: {
            path: path.join(__dirname, "dist"),
            filename: "app.[hash:16].js",
        },
        plugins: [
            new MiniCssExtractPlugin({
                filename: "[name].css",
                ignoreOrder: false,
            }),
            new htmlWebpackPlugin({
                filename: "index.html",
                template: "./public/index.html",
                minify: {
                    collapseWhitespace: false,
                },
                inject: true,
            }),
        ],
        devServer: {
            contentBase: path.join(__dirname, "dist"),
            compress: true,
            port: 9000, // 配置端口
            hot: true,
        },

        module: {
            rules: [
                {
                    test: /.js$/,
                    exclude: /(node_modules|bower_components)/,
                    use: "babel-loader",
                },
                {
                    test: /.css$/,
                    use: [
                        MiniCssExtractPlugin.loader,
                        "css-loader",
                        {
                            loader: "postcss-loader", //使用postcss
                        },
                    ],
                },
            ],
        },
    };

postCSS 参考: http://postcss.docschina.org/

postcss-loader 参考: https://webpack.docschina.org/loaders/postcss-loader/