From d9dc638cb59e2588bf452caa8143d8b756bc7a58 Mon Sep 17 00:00:00 2001
From: lambk <kyle.lamb@hotmail.co.nz>
Date: Sat, 15 Jun 2019 18:55:22 +1200
Subject: [PATCH] Add support for reversing a grouped category title on
 tooltips

- Setting the new reverseTitle option on the chart.tooltip object will result in the tooltip title being displayed as <high_level_category>, <middle_level_category>, <low_level_category> rather than the default low to high order

- If the option is omitted, it defaults to false
---
 grouped-categories.js | 15 +++++++++++----
 1 file changed, 11 insertions(+), 4 deletions(-)

diff --git a/grouped-categories.js b/grouped-categories.js
index cf85233..c45b448 100644
--- a/grouped-categories.js
+++ b/grouped-categories.js
@@ -43,10 +43,11 @@
 		return JSON.parse(JSON.stringify(thing));
 	}
 
-	function Category(obj, parent) {
+	function Category(obj, parent, reverseTooltipTitle) {
 		this.userOptions = deepClone(obj);
 		this.name = obj.name || obj;
 		this.parent = parent;
+		this.reverseTooltipTitle = reverseTooltipTitle;
 
 		return this;
 	}
@@ -59,6 +60,9 @@
 			parts.push(cat.name);
 			cat = cat.parent;
 		}
+		if (this.reverseTooltipTitle) {
+			parts = parts.reverse();
+		}
 
 		return parts.join(', ');
 	};
@@ -76,8 +80,8 @@
 	}
 
 	// Adds category leaf to array
-	function addLeaf(out, cat, parent) {
-		out.unshift(new Category(cat, parent));
+	function addLeaf(out, cat, parent, reverseTooltipTitle) {
+		out.unshift(new Category(cat, parent, reverseTooltipTitle));
 
 		while (parent) {
 			parent.leaves = parent.leaves ? (parent.leaves + 1) : 1;
@@ -102,7 +106,7 @@
 				}
 				buildTree(cat.categories, out, options, cat, depth + 1);
 			} else {
-				addLeaf(out, cat, parent);
+				addLeaf(out, cat, parent, options.reverseTooltipTitle);
 			}
 		}
 		options.depth = mathMax(options.depth, depth);
@@ -164,9 +168,12 @@
 			reverseTree = [],
 			stats = {},
 			labelOptions = this.options.labels,
+			tooltipOptions = this.chart.options.tooltip,
 			userAttr = labelOptions.groupedOptions,
 			css = labelOptions.style;
 
+		stats.reverseTooltipTitle = tooltipOptions.reverseTitle || false;
+
 		// build categories tree
 		buildTree(categories, reverseTree, stats);