http request and read practice

caller.js

const http = require('http')

const theRequest = http.request({
    host: 'localhost',
    path: '/',
    port: 3000,
    method: 'POST',
    headers: {
        'message': "this is a message included in the header"
    },
    body: JSON.stringify({
        "message": "this is located in body in option"
    })
}, function (res) {
    var str = '';
    res.on('data', function (chunk) {
        str += chunk;
    });
    res.on('end', function () {});
})

theRequest.on('error', (err) => {
    console.log("request error occured")
    console.log(err)
})
theRequest.write(
    JSON.stringify({
        message: "this is located in write"
    })
)
theRequest.end();