index.js

var server=require('./server')
server.start();

server.js

var http=require('http')
function start(){
var onrequest=function(req,res){
res.writeHead(200,{'Content-Type':'text/plain'})
res.write('hello,world!')
res.end()
}

var server=http.createServer(onrequest)
server.listen(8000)
console.log('done')}
exports.start=start;