From d05e25ef72f390d76d67a88b0d678d1ebbc109db Mon Sep 17 00:00:00 2001
From: Patrick Hulin <patrick.hulin@gmail.com>
Date: Sat, 12 Oct 2024 12:44:00 -0400
Subject: [PATCH 1/2] perf: Memoize getFoldGroup.

---
 src/lib.ts | 15 +++++++++++++--
 1 file changed, 13 insertions(+), 2 deletions(-)

diff --git a/src/lib.ts b/src/lib.ts
index 5bc3884909..3a68f3ba04 100644
--- a/src/lib.ts
+++ b/src/lib.ts
@@ -455,12 +455,23 @@ export function isCurrentFamiliar(familiar: Familiar): boolean {
  *
  * @category General
  * @param item Item that is part of the required fold group
+ * @param cache Whether to query the fold group cache
  * @returns List of items in the fold group
  */
-export function getFoldGroup(item: Item): Item[] {
-  return Object.entries(getRelated(item, "fold"))
+const foldGroupCache = new Map<Item, Item[]>();
+export function getFoldGroup(item: Item, cache = true): Item[] {
+  if (cache) {
+    const cached = foldGroupCache.get(item);
+    if (cached !== undefined) return cached;
+  }
+
+  const result = Object.entries(getRelated(item, "fold"))
     .sort(([, a], [, b]) => a - b)
     .map(([i]) => Item.get(i));
+  for (const fold of result) {
+    foldGroupCache.set(fold, result);
+  }
+  return result;
 }
 
 /**

From 97de4ab64f1a765ac6908847dca872b7b8772d0e Mon Sep 17 00:00:00 2001
From: Patrick Hulin <patrick.hulin@gmail.com>
Date: Sat, 12 Oct 2024 12:48:47 -0400
Subject: [PATCH 2/2] lint

---
 src/lib.ts | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/lib.ts b/src/lib.ts
index 3a68f3ba04..0902448d10 100644
--- a/src/lib.ts
+++ b/src/lib.ts
@@ -450,6 +450,8 @@ export function isCurrentFamiliar(familiar: Familiar): boolean {
   return myFamiliar() === familiar;
 }
 
+const foldGroupCache = new Map<Item, Item[]>();
+
 /**
  * Determines the fold group (if any) of which the given item is a part
  *
@@ -458,7 +460,6 @@ export function isCurrentFamiliar(familiar: Familiar): boolean {
  * @param cache Whether to query the fold group cache
  * @returns List of items in the fold group
  */
-const foldGroupCache = new Map<Item, Item[]>();
 export function getFoldGroup(item: Item, cache = true): Item[] {
   if (cache) {
     const cached = foldGroupCache.get(item);