[Node.js] 이벤트 리스너를 추가한 간단한 웹서버 구현

const port = 3000,
    http = require("http"),
    httpStatus = require("http-status-codes"),
    app = http.createServer();
app.on("request",(req, res)=>{//이벤트리스너
	res.writeHead(httpStatus.OK,{
    	"Content-Type":"text/html"
        });
    let responseMessage ="<h1>This is message.</h1>;
    res.end(responseMessage);
});