node.js createServer

const http=require(‘http‘)
const fs=require(‘fs‘)
const path=require(‘path‘)
const server=http.createServer(function(req,res){
    const {url}=req
    console.log(url,‘.‘+url)
    const reg=/\w+\.(html|css|js)$/
    const obj=reg.exec(url)
    console.log(obj)
    if(obj){
        switch(obj[1]){
            case ‘html‘:
                fs.readFile(‘.‘+url,(err,data)=>{
                    if(err) return console.log(err)
                    res.end(data)
                })
                break
            case ‘css‘:
                fs.readFile(path.join(‘.‘,‘css‘,obj[0]),(err,data)=>{
                    if(err) return console.log(err)
                    res.end(data)
                })
                break
            case ‘js‘:
                fs.readFile(path.join(‘.‘,‘js‘,obj[0]),(err,data)=>{
                    if(err) return console.log(err)
                    res.end(data)
                })
                break
            default:
                res.end(`
                    <h1>404 not found</h1>
                    <span>span</span>
                `)
        }
    }
    console.log(‘=============‘)
})

server.listen(8080,()=>console.log(‘server.listen @_@‘))