From 8f42232105d0dc23d951ae093ba1b52899606ea5 Mon Sep 17 00:00:00 2001
From: gorhill <rhill@raymondhill.net>
Date: Sun, 14 May 2017 12:01:56 -0400
Subject: [PATCH] fix #2609

---
 src/js/contentscript.js | 36 +++++++++++++++++-------------------
 1 file changed, 17 insertions(+), 19 deletions(-)

diff --git a/src/js/contentscript.js b/src/js/contentscript.js
index 5d313d6df..dab855408 100644
--- a/src/js/contentscript.js
+++ b/src/js/contentscript.js
@@ -233,7 +233,7 @@ var platformHideNode = vAPI.hideNode,
     var uid,
         timer,
         observer,
-        changedNodes = [],
+        changedNodes = new Set(),
         observerOptions = {
             attributes: true,
             attributeFilter: [ 'style' ]
@@ -256,34 +256,33 @@ var platformHideNode = vAPI.hideNode,
     //   on sites which try to use inline styles to bypass blockers.
     var batchProcess = function() {
         timer.clear();
-        var cNodes = changedNodes, i = cNodes.length,
-            vNodes = [], j = 0,
-            node;
-        while ( i-- ) {
-            node = cNodes[i];
-            if ( node[uid] !== undefined && node.clientHeight && node.clientWidth ) {
-                vNodes[j++] = node;
+        var uid_ = uid;
+        for ( var node of changedNodes ) {
+            if (
+                node[uid_] === undefined ||
+                node.clientHeight === 0 || node.clientWidth === 0
+            ) {
+                continue;
             }
-        }
-        cNodes.length = 0;
-        while ( j-- ) {
-            node = vNodes[j];
             var attr = node.getAttribute('style');
-            if ( !attr ) {
+            if ( attr === null ) {
                 attr = '';
-            } else {
+            } else if (
+                attr.length !== 0 &&
+                attr.charCodeAt(attr.length - 1) !== 0x3B /* ';' */
+            ) {
                 attr += '; ';
             }
             node.setAttribute('style', attr + 'display: none !important;');
         }
+        changedNodes.clear();
     };
 
     var observerHandler = function(mutations) {
         var i = mutations.length,
-            cNodes = changedNodes,
-            j = cNodes.length;
+            changedNodes_ = changedNodes;
         while ( i-- ) {
-            cNodes[j++] = mutations[i].target;
+            changedNodes_.add(mutations[i].target);
         }
         timer.start();
     };
@@ -297,8 +296,7 @@ var platformHideNode = vAPI.hideNode,
             node[uid] = node.hasAttribute('style') && (node.getAttribute('style') || '');
         }
         // Performance: batch-process nodes to hide.
-        var cNodes = changedNodes;
-        cNodes[cNodes.length] = node;
+        changedNodes.add(node);
         timer.start();
         if ( observer === undefined ) {
             observer = new MutationObserver(observerHandler);