index.js

import longPoll from './lib/longPoll';
longPoll("http://example.com/livereload", (err,res) => {
    if(err){
      console.log("error");
      console.log(err);
    } else {
      console.log("reloading");
      console.log(res);
    }
  });

longPoll.js

import request from './request';

export default (urlToPoll,callback) => {
    let makeRequest = () =>{
      request({
        url:urlToPoll,
        timeout: 1000
      })
      .then((data)=> {
        callback(null,data);
      })
      .catch(callback);
    }
    makeRequest();
    setInterval(makeRequest,10000);

}

request.js

export default (props = {} ) => {
    return new Promise((resolve,reject) => {
        const XHR = new XMLHttpRequest();

        // Configuring XHR instance to load data that we need.
        XHR.open('GET', props.url);
        if( props.timeout ){
          XHR.timeout = props.timeout;
        }
        XHR.addEventListener('abort', reject);
        // Adding event listener to retreive data when it will be loaded.
        XHR.addEventListener('load', event => {
            // Parsing request response to JSON and resolving promise
            resolve(JSON.parse(event.target.responseText));
        });
        XHR.addEventListener('error', reject);
        // Initiating request.
        XHR.send();
    });
}