poller_promises.js

// =======================================================
// Poller.js
// =======================================================
const EventEmitter = require('events');

class Poller extends EventEmitter {
    /**
     * @param {int} timeout how long should we wait after the poll started?
     */
    constructor(timeout = 100) {
        super();
        this.timeout = timeout;
    }

    poll() {
        setTimeout(() => this.emit('poll'), this.timeout);
    }

    onPoll(cb) {
        this.on('poll', cb);
    }
}

module.exports = Poller;


// =======================================================
// index.js
// =======================================================
const Poller = require('./Poller');

// Set 1s timeout between polls
// note: this is previous request + processing time + timeout
let poller = new Poller(1000); 

// Wait till the timeout sent our event to the EventEmitter
poller.onPoll(() => {
    console.log('triggered');
    poller.poll(); // Go for the next poll
});

// Initial start
poller.poll();