Native nodejs websocket server with http module + no libraries

websocket-server.js

const http = require("http")
const crypto = require("crypto") 

const server = http.createServer((req,res)=>{
    res.write("hi")
    res.end()
})

server.on("upgrade",(req,socket)=>{
	const accept = crypto.Hash("sha1").update(req.headers["sec-websocket-key"]+"258EAFA5-E914-47DA-95CA-C5AB0DC85B11").digest("base64")
	const headers = [
		'HTTP/1.1 101 Switching Protocols',
		'Upgrade: WebSocket',
		'Connection: Upgrade',
		'Sec-WebSocket-Accept: '+accept,
		''
	].map(line => line.concat('\r\n')).join('')
	socket.write(headers)
	socket.on('data', (bytes) => {
  	console.log(parseData(bytes))
		sendData("hi from server")
	})

	const sendData = (data) => {
		let obj = []
		obj[0] = 129
		if (data.length < 126) {
			obj[1] = data.length
			for (let i = 0; i < data.length; i++) {
				obj[i+2] = parseInt(data[i].charCodeAt(0).toString(2),2)
			}
		} else if (data.length <= 65535) {
			obj[1] = 126
			for (let i = 0; i < 3; i++) {
				obj[i+2] = parseInt(data.length.toString(2).padStart(16,"0").substring(i*8,i*8+8),2)
			}
			for (let i = 4; i < data.length; i++) {
				obj[i] = parseInt(data[i].charCodeAt(0).toString(2),2)
			}
		} else if (data.length < 18446744073709551615) {
			obj[1] = 127
			for (let i = 0; i < 8; i++) {
				obj[i+2] = parseInt(data.length.toString(2).padStart(64,"0").substring(i*8,i*8+8),2)
			}
			for (let i = 9; i < data.length; i++) {
				obj[i] = parseInt(data[i].charCodeAt(0).toString(2),2)
			}
		} else {
			console.log("data too big")
		}
		socket.write(Uint8Array.from(obj))
	}

	const parseData = (bytes) => {
		const length = bytes[1] - 128 < 126 ? 1 : bytes == 126 ? 2 : 8 
		const maskKey = bytes.slice(length+1,length+5)
		const data = bytes.slice(length+5)
		return String.fromCharCode.apply(null,data.map((byte,i)=>byte^maskKey[i%4]))
	}
	socket.on("error",(err)=>{
		console.log(err)
	})
	socket.on("end",()=>{
		console.log("disconnect")
	})
})

server.listen(80, () => {
  console.log("Started.")
})