From 848a7f4e744c8f4dcb4ec88a0e99c4ae6aac25e5 Mon Sep 17 00:00:00 2001
From: Jermolene <jeremy@jermolene.com>
Date: Mon, 6 Jul 2015 11:23:12 +0100
Subject: [PATCH] Optimise getStateQualifier()
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Another fix for #1864, this time we’re caching state qualifiers as they
are expensive to compute.
---
 core/modules/widgets/widget.js | 21 ++++++++++++++-------
 1 file changed, 14 insertions(+), 7 deletions(-)

diff --git a/core/modules/widgets/widget.js b/core/modules/widgets/widget.js
index 53c5ea46b..679433071 100755
--- a/core/modules/widgets/widget.js
+++ b/core/modules/widgets/widget.js
@@ -195,16 +195,23 @@ Widget.prototype.hasVariable = function(name,value) {
 Construct a qualifying string based on a hash of concatenating the values of a given variable in the parent chain
 */
 Widget.prototype.getStateQualifier = function(name) {
+	this.qualifiers = this.qualifiers || Object.create(null);
 	name = name || "transclusion";
-	var output = [],
-		node = this;
-	while(node && node.parentWidget) {
-		if($tw.utils.hop(node.parentWidget.variables,name)) {
-			output.push(node.getVariable(name));
+	if(this.qualifiers[name]) {
+		return this.qualifiers[name];
+	} else {
+		var output = [],
+			node = this;
+		while(node && node.parentWidget) {
+			if($tw.utils.hop(node.parentWidget.variables,name)) {
+				output.push(node.getVariable(name));
+			}
+			node = node.parentWidget;
 		}
-		node = node.parentWidget;
+		var value = $tw.utils.hashString(output.join(""));
+		this.qualifiers[name] = value;
+		return value;
 	}
-	return $tw.utils.hashString(output.join(""));
 };
 
 /*