01.js

const request = require('request-promise');
const fs = require('fs');

let lastResponse = null;
let start = 1462118375688;


const intervals = [];

const makeRequest = () => {
    return request('http://www.radiohead.com/01');
}

const formatElapsedTime = (s, e) => {

    const elapsed = e - s;

    return Math.floor((elapsed / 1000)).toString();

};

const runRequest = () => {

    setTimeout(function () {

        const requestPending = makeRequest();
        console.log('Request at ' + Date.now());

        requestPending
            .then(res => {

                if (!lastResponse) {
                    lastResponse = res;
                } else {
                    if (lastResponse !== res) {
                        const end = Date.now();
                        lastResponse = res;
                        try {
                            console.log('Writing!');
                            fs.appendFileSync('./log.txt', `${res}\n${end}\n${formatElapsedTime(start, end).toString()}\n\n`);
                            start = end;
                        } catch (e) {
                        }
                    }
                }

                runRequest();

            })
            .then(null, function (err) {
                console.error(err);
                runRequest();
            });

    }, 200);

};

runRequest();