Convert incoming chunks to uppercase

uppercaserer.js

var http = require('http')
var fs = require('fs')
var map = require('through2-map')
var server = http.createServer((req, res) => {
    
    res.writeHead(200,{'Content-type':'text/plain'})
    if(req.method != 'POST'){
        return res.end('send me a POST\n')
    }
    req.pipe(map(chunk=>{
        return chunk.toString().toUpperCase()
    })).pipe(res)
})
server.listen(process.argv[2])