fix(ngTouch): update workaround for desktop Webkit quirk

Fix click busting of input click triggered by a label click quickly
following a touch event on a different element, in desktop
and mobile WebKit

To reproduce the issue fixed by this commit set up a page with
 - an element with ng-click
 - a radio button (with hg-model) and associated label
In a quick sequence tap on the element and then on the label.
The radio button will not be checked, unless PREVENT_DURATION has passed

Closes #6302

1 files changed, 15 insertions, 1 deletions

diff --git a/src/ngTouch/directive/ngClick.js b/src/ngTouch/directive/ngClick.js
index 6cd0ff76..7e558def 100644
--- a/src/ngTouch/directive/ngClick.js
+++ b/src/ngTouch/directive/ngClick.js
@@ -53,6 +53,7 @@ ngTouch.directive('ngClick', ['$parse', '$timeout', '$rootElement',
   var ACTIVE_CLASS_NAME = 'ng-click-active';
   var lastPreventedTime;
   var touchCoordinates;
+  var lastLabelClickCoordinates;
 
 
   // TAP EVENTS AND GHOST CLICKS
@@ -124,10 +125,23 @@ ngTouch.directive('ngClick', ['$parse', '$timeout', '$rootElement',
     var y = touches[0].clientY;
     // Work around desktop Webkit quirk where clicking a label will fire two clicks (on the label
     // and on the input element). Depending on the exact browser, this second click we don't want
-    // to bust has either (0,0) or negative coordinates.
+    // to bust has either (0,0), negative coordinates, or coordinates equal to triggering label
+    // click event
     if (x < 1 && y < 1) {
       return; // offscreen
     }
+    if (lastLabelClickCoordinates &&
+        lastLabelClickCoordinates[0] === x && lastLabelClickCoordinates[1] === y) {
+      return; // input click triggered by label click
+    }
+    // reset label click coordinates on first subsequent click
+    if (lastLabelClickCoordinates) {
+      lastLabelClickCoordinates = null;
+    }
+    // remember label click coordinates to prevent click busting of trigger click event on input
+    if (event.target.tagName.toLowerCase() === 'label') {
+      lastLabelClickCoordinates = [x, y];
+    }
 
     // Look for an allowable region containing this click.
     // If we find one, that means it was created by touchstart and not removed by