Comparison between getting data from Firebase using sync and async

test.js

// PART 1a - Uncomment the following lines if running on Node;
// var _ = require("lodash");
// var Firebase = require('firebase');

// PART 1b - Uncomment the following lines if running on Chrome Dev Tool;
// var script = document.createElement('script');
// script.type = 'text/javascript';
// script.src = 'https://cdnjs.cloudflare.com/ajax/libs/lodash.js/3.10.1/lodash.min.js';
// document.head.appendChild(script);
// var script = document.createElement('script');
// script.type = 'text/javascript';
// script.src = 'https://cdn.firebase.com/js/client/2.3.2/firebase.js';
// document.head.appendChild(script);

// PART2 - Rewrite firebaseRef to point to the location you wish to get data from;
var firebaseRef = 'https://<your_firebase_ref>.firebaseio.com';

// To be able to log elapsed time on both Node and browser;
var logElapseTime = function (_endLabel) {
  try {
    if (_endLabel) {
      return process.hrtime(_endLabel);
    }
    return process.hrtime();
  }catch (e) {
    return window.performance.now();
  }
};

var haha = logElapseTime();
// Sync Approach;
console.log('Running sync task...\n');
firebaseRef.once('value', function (snapshot) {
  if (snapshot) {
    var hahaEnd = logElapseTime(haha);
    console.log('\n1) Time spent on sync: %dms', _.isArray(hahaEnd) ? (hahaEnd[0] * 1E3 + hahaEnd[1] * 1E-6).toFixed(3) : (hahaEnd - haha));
  }
});
var haha2 = logElapseTime();
firebaseRef.once('value', function (snapshot) {
  if (snapshot) {
    var hahaEnd2 = logElapseTime(haha2);
    console.log('\n2) Time spent on sync 2: %dms', _.isArray(hahaEnd2) ? (hahaEnd2[0] * 1E3 + hahaEnd2[1] * 1E-6).toFixed(3) : (hahaEnd2 - haha2));
  }
});

console.log('Separator...\n');

// Async approach using ES2015's Promise;
var lol = logElapseTime();
console.log('Running async task...\n');
var _p1 = new Promise(function (resolve, reject) {
  firebaseRef.once('value', function (snapshot) {
    resolve(snapshot);
  });
});

var _p2 = new Promise(function (resolve, reject) {
  firebaseRef.once('value', function (snapshot) {
    resolve(snapshot);
  });
});

Promise.all([_p1, _p2]).then(function (value) {
  if (value) {
    var lolEnd = logElapseTime(lol);
    console.log('\n3) Time spent on async: %dms', _.isArray(lolEnd) ? (lolEnd[0] * 1E3 + lolEnd[1] * 1E-6).toFixed(3) : (lolEnd - lol));
  }
});

// Running successive async tasks using ES2015's Promise;
// TAT reduces after all;
var successiveIdx = 4;
// stop running successive async tasks after 60s;
var stopSuccessiveTimer = 60;
var successiveTimer = setInterval(function () {
  console.log('\n\n#############################');
  console.log('Successive Separator...\n');
  var successive = logElapseTime();
  console.log('Running successive async tasks...');
  var _p3 = new Promise(function (resolve, reject) {
    firebaseRef.once('value', function (snapshot) {
      resolve(snapshot);
    });
  });

  var _p4 = new Promise(function (resolve, reject) {
    firebaseRef.once('value', function (snapshot) {
      resolve(snapshot);
    });
  });

  Promise.all([_p4, _p3]).then(function (value) {
    if (value) {
      var successiveEnd = logElapseTime(successive);
      console.log('\n%d) Time spent on successive async: %dms', successiveIdx, _.isArray(successiveEnd) ? (successiveEnd[0] * 1E3 + successiveEnd[1] * 1E-6).toFixed(3) : (successiveEnd - successive));
    }
  });

  successiveIdx++;
}, 1000);

setTimeout(function () {
  clearTimeout(successiveTimer);
}, (stopSuccessiveTime * 1000));