Idler, micro JS lib for binding callbacks to user interactivity and idling.

Idler.js

/**
 *	Idler
 *
 *	API for binding to user interaction. Created by passing two callbacks, one
 *	to run on idle and another to run on user interaction resumed. Idler optionally
 *	takes a third argument, idleTime which defines the period of inactivity required
 *	to declare a user idled (in ms).
 *
 *	Example usage:
 *
 *	// Instantiates an instance
 *	//
 *	var i = new Idler(
 *		function () {console.warn("Idling...");}, 
 *		function () {console.info("Resuming"); }, 
 *		100000		// = 100 seconds
 *	);
 *
 *
 *	// Destroys instance cleanly
 *	//
 *	i.destroy();
 *
 */
(function () {
	"use strict";
	
	var Idler = function (onIdle, onInteraction, idleTime) {
		idleTime = idleTime || 60 * 1000;
		
		this.onIdle = onIdle;
		this.onInteraction = onInteraction;
		this.idleTime = idleTime;
		this.isIdle = false;
		
		Idler.initInterval();
		
		Idler.instances.push(this);
	};
	
	Idler.getTime = function () {
		return +new Date;
	};
	
	Idler.instances = [];
	Idler.intervalTimer = null;
	
	Idler.lastInteraction = Idler.getTime();
	
	Idler.prototype.destroy = function (instance) {
		Idler.instances.splice(Idler.instances.indexOf(this), 1);
		
		if (Idler.instances.length == 0) {
			clearInterval(Idler.intervalTimer);
			Idler.intervalTimer = null;
		}
	};
	
	Idler.prototype.setIdle = function () {
		this.isIdle = true;
		this.onIdle();	
	};
	
	Idler.setIdle = function () {
		Idler.forEach(function (instance) {
			instance.setIdle();
		});
	};
	
	Idler.reset = function () {
		Idler.lastInteraction = Idler.getTime();
		Idler.forEach(function (instance) {
			if (!instance.isIdle)
				return;
			instance.isIdle = false;
			instance.onInteraction();
		});
	};
	
	Idler.handleTabChange = function (hidden) {
		if (hidden)
			Idler.setIdle();
		else
			Idler.reset();
	};
	
	Idler.forEach = function (fn) {
		for (var i = 0; i < Idler.instances.length; i++)
			try {
				fn(Idler.instances[i]);
			} catch (e) {
				console.error(e);
			}
	};
	
	Idler.update = function () {
		var t = Idler.getTime();
		Idler.forEach(function (instance) {
			if (instance.isIdle)
				return;
			if (instance.idleTime + Idler.lastInteraction < t)
				instance.setIdle();
		});
	};
	
	Idler.initInterval = function () {
		if (Idler.intervalTimer === null)
			Idler.intervalTimer = setInterval(Idler.update, 1000);	
	};
	
	document.addEventListener((function () {
		var browserSpecific = {
			webkitHidden: "webkitvisibilitychange",
			msHidden: "msvisibilitychange",
			mozHidden: "mozvisibilitychange"
		};
		for (var key in browserSpecific) {
			if (key in document)
				return browserSpecific[key];
		}
		return "visibilitychange";
	})(), function (e) {
		var vendor = e.type.replace("visibilitychange", "");
		Idler.handleTabChange(document[vendor != "" ? vendor + "Hidden" : "hidden"]);
	});
	
	window.onmousemove = Idler.reset;
	window.onmousedown = Idler.reset;
	window.onclick = Idler.reset;
	window.onscroll = Idler.reset;
	window.onkeypress = Idler.reset;
	window.onkeyup = Idler.reset;
	
	window.Idler = Idler;
})();