Basic hysteresis for riveted.js

riveted.js.patch

commit 0fe549297387bf971f96154d9339ed7ee478a029
Author: Aur Saraf <sonoflilit@gmail.com>
Date:   Thu Jun 5 03:18:14 2014 +0300

    google analytics activity tracking

diff --git a/v3/js/riveted.js b/v3/js/riveted.js
index 5d8bf9e..b337113 100644
--- a/v3/js/riveted.js
+++ b/v3/js/riveted.js
@@ -20,6 +20,13 @@ var riveted = (function() {
       classicGA,
       googleTagManager;
 
+    var activityMeasure = 0,
+      highActivityValue = 30,
+      lowActivityValue = 10,
+      activityThreshold = 60,
+      activityCooldownFactor = 0.8,
+      lastActivity = startTime;
+
     /*
      * Determine which version of GA is being used
      * "ga", "_gaq", and "dataLayer" are the possible globals
@@ -51,10 +58,10 @@ var riveted = (function() {
       }
 
       // Basic activity event listeners
-      addListener(document, 'keydown', trigger);
-      addListener(document, 'click', trigger);
-      addListener(window, 'mousemove', throttle(trigger, 500));
-      addListener(window, 'scroll', throttle(trigger, 500));
+      addListener(document, 'keydown', lowActivity);
+      addListener(document, 'click', highActivity);
+      addListener(window, 'mousemove', throttle(lowActivity, 500));
+      addListener(window, 'scroll', throttle(lowActivity, 500));
 
       // Page visibility listeners
       addListener(document, 'visibilitychange', visibilityChange);
@@ -208,6 +215,27 @@ var riveted = (function() {
 
     }
 
+    function activity(amount) {
+      var time = new Date();
+      var elapsed = (time - lastActivity) / 1000;
+      lastActivity = time;
+      activityMeasure *= Math.pow(activityCooldownFactor, elapsed);
+
+      activityMeasure += amount;
+
+      if (activityMeasure >= activityThreshold) {
+        trigger();
+      }
+    }
+
+    function highActivity() {
+      activity(highActivityValue);
+    }
+
+    function lowActivity() {
+      activity(lowActivityValue);
+    }
+
     function trigger() {
 
       if (!started) {