Get speed Metrics and send them to Google Analytics

abGAsendTime.js

abGAsendTime = function(){


  this.getLoadTime = function() {

    return performance.timing.loadEventStart - performance.timing.navigationStart;

  }


  this.getTimeToFirstByte = function() {

    var timing = window.performance.timing;

    return timing.responseStart - timing.navigationStart;

  }


  this.getFirstPaintTime = function() {

    if ( ! 'chrome' in window )  return false; 

    var load = window.chrome.loadTimes();

    var firstPaintTime = (load.firstPaintTime - load.startLoadTime) * 1000;

    return Math.round(firstPaintTime);

  } 


  this.getContentfulPaint = function() {

    //first-contentful-paint
    if ( "getEntriesByType" in performance ) return  Math.round( performance.getEntriesByType('paint')[1].startTime );
        
    return false;

  }


  this.sendToGA = function(connection) {

    ga( 'send', 'timing', 'abView', 'loadTime', this.getLoadTime() );

    ga( 'send', 'timing', 'abView', 'firstPaintTime', this.getFirstPaintTime() );

    ga( 'send', 'timing', 'abView', 'timeToFirstByte', this.getTimeToFirstByte() );

    ga( 'send', 'timing', 'abView', 'firstContentfulPaint',  this.getContentfulPaint() );

    return true; 
    
  }



  this.track = function() {
    
    if( 'performance' in window )  this.sendToGA();

  }


  this.init = function(){

    if (typeof ga === 'function') this.track();

    else setTimeout(this.init,500);

  }



}


var myGATime = new abGAsendTime();

myGATime.init();