devServer

开发环境下，启动一个web服务，模拟用户从浏览器访问我们的web服务。
npm install webpack-dev-serveer html-webpack-plugin

const HtmlWebpackPlugin = require('html-webpack-plugin')
const path = require('path')
module.exports = {
    mode: "development",
    entry: './app.js',
    output: {
        publicPath: "/",
        clean: true
    },
    module: {
        rules: [
            {
                test: /\.js$/,
                exclude: /node_modules/,
                use: {
                    loader: "babel-loader",
                    options: {
                        presets: ['@babel/preset-env']
                    }
                }
            }
        ]
    },
    devtool: 'source-map',
    devServer: {
        static: path.resolve(__dirname, './dist'),
        // 是否在服务器端进行压缩
        compress: true,
        // https: true,
        // http2: true
        // 服务的端口号
        // port:3000,
        host:'0.0.0.0',
        // 服务器传给浏览器的信息
        headers: {
            'X-Access-Token': 'test123'
        },
        // 跨域
        proxy: {
            // 请求/api这个接口就会自动变成请求http://localhost:9000/api
            '/api': 'http://localhost:9000'
        },
        historyApiFallback:true,
    },
    plugins: [
        new HtmlWebpackPlugin()
    ]
}