Quick & Dirty tracker of user UI

user-interaction-stats.js

/*
  Allows to quickly asses amount of work (clickes, key presses, page reloads)
  users have to do while performing a task.
  Usage:
      var tracker = new UserInteractoinStats(); // once you will begin doing the stats
      // Once you want to see results
      tracker.stats();
   This will also survive page loads, using local storage.
   If you want to clear all data, just :
       tracker.clear()
   If you want to run multiple trackers at the same time, you can
   shard their counters using a prefixed name. Just initialize the
   tracker with the name you want:
        tracker = new UserInteractionStats("fillLoginForm");
        // do part of the work here
        tracker = new UserInteractionStats("errorCorrection");
        // more ui interaction goes on
        tracker.stats('fillLoginForm'); // user the fillLoginForm
        tracker.stats('errorCorrection')
*/

function UserInteractionStats(name){
    name = name || "anon";
    var self = this;
    this.keyPressedKey = name + 'numKeypresses'; 
    this.mousePressedKey = name + 'numClick'; 
    this.pageLoadedKey = name + 'numPageLoads'; 
    this.startedAtKey = name + 'startedAt'; 
    this.reset();
    
    this.keyPressed = function(){
        return self.incr(self.keyPressedKey);
    };
    this.mousePressed = function(){
        return self.incr(self.mousePressedKey)
    };
    this.pageLoaded = function(){
        return self.incr(self.pageLoadedKey);
    };
    if (!sessionStorage.getItem(this.startedAtKey)){
     sessionStorage.setItem(this.startedAtKey)
    }
    document.addEventListener('keyup', this.keyPressed)
    document.addEventListener('click', this.mousePressed)
    window.addEventListener('beforeunload', this.pageLoaded)

}

UserInteractionStats.prototype.incr = function(propName){
    sessionStorage.setItem(propName, parseInt(sessionStorage.getItem(propName) || 0) + 1);
    return true;
}

UserInteractionStats.prototype.stats = function(){
    console.log("Key Presses: " + sessionStorage.getItem(this.keyPressedKey));
    console.log("Mouse Clicks: " + sessionStorage.getItem(this.mousePressedKey)) ;
    console.log("Page Loads: " + sessionStorage.getItem(this.pageLoadedKey));
    var t = Math.floor(new Date().getTime() - parseInt(sessionStorage.getItem(this.startedAtKey)) / 1000)/1000
    console.log("Time: " + t);
}


UserInteractionStats.prototype.reset = function(){
    document.removeEventListener('keyup', this.keyPressed, false)
    document.removeEventListener('click', this.mousePressed, false)
    window.removeEventListener('beforeunload', this.pageLoaded, false)
}
UserInteractionStats.prototype.clear = function(){
    sessionStorage.removeItem(this.keyPressedKey, 0);
    sessionStorage.removeItem(this.mousePressedKey, 0);
    sessionStorage.removeItem(this.startedAtKey, 0);
    sessionStorage.removeItem(this.pageLoadedKey, 0);
}