二、loader 处理css

webpack只能理解js和json,如果要处理非js的文件，必须使用一些对应的loader

1-1 安装loader

yarn add css-loader style-loader

const path = require("path");
const HtmlWebpackPlugin  = require("html-webpack-plugin");
module.exports = {
    entry:path.join(__dirname,'src/main.js'),
    output:{
        filename:"bundle.js",
        path:path.join(__dirname,"dist")
    },
    module:{
        rules:[
            {
                test:/\.css$/,
                use:['style-loader','css-loader']
            }
        ]
    },
    mode:"development"
}