From ea2043c0eb2fad05d05f3dfecfa76c868030099a Mon Sep 17 00:00:00 2001
From: gorhill <rhill@raymondhill.net>
Date: Sun, 4 Jan 2015 10:03:51 -0500
Subject: [PATCH] auto cleanup of listeners

---
 src/js/udom.js | 37 +++++++++++++++++++++++++++++++++++--
 1 file changed, 35 insertions(+), 2 deletions(-)

diff --git a/src/js/udom.js b/src/js/udom.js
index 1d90f865d..0ff92e483 100644
--- a/src/js/udom.js
+++ b/src/js/udom.js
@@ -20,7 +20,6 @@
 */
 
 /* exported uDom */
-'use strict';
 
 /******************************************************************************/
 
@@ -32,6 +31,8 @@
 
 var uDom = (function() {
 
+'use strict';
+
 /******************************************************************************/
 
 var DOMList = function() {
@@ -639,6 +640,24 @@ DOMList.prototype.toggleClasses = function(classNames, targetState) {
 
 /******************************************************************************/
 
+var listenerEntries = [];
+
+var ListenerEntry = function(target, type, capture, callback) {
+    this.target = target;
+    this.type = type;
+    this.capture = capture;
+    this.callback = callback;
+    target.addEventListener(type, callback, capture);
+};
+
+ListenerEntry.prototype.dispose = function() {
+    this.target.removeEventListener(this.type, this.callback, this.capture);
+    this.target = null;
+    this.callback = null;
+};
+
+/******************************************************************************/
+
 var makeEventHandler = function(selector, callback) {
     return function(event) {
         var dispatcher = event.currentTarget;
@@ -662,7 +681,7 @@ DOMList.prototype.on = function(etype, selector, callback) {
 
     var i = this.nodes.length;
     while ( i-- ) {
-        this.nodes[i].addEventListener(etype, callback, selector !== undefined);
+        listenerEntries.push(new ListenerEntry(this.nodes[i], etype, selector !== undefined, callback));
     }
     return this;
 };
@@ -693,6 +712,20 @@ DOMList.prototype.trigger = function(etype) {
 
 /******************************************************************************/
 
+// Cleanup
+
+var onBeforeUnload = function() {
+    var entry;
+    while ( entry = listenerEntries.pop() ) {
+        entry.dispose();
+    }
+    window.removeEventListener('beforeunload', onBeforeUnload);
+};
+
+window.addEventListener('beforeunload', onBeforeUnload);
+
+/******************************************************************************/
+
 return DOMListFactory;
 
 })();