From 533e0094a17399e856e2bedc2ab20f26bbf8c6fc Mon Sep 17 00:00:00 2001
From: Joachim Viide <jviide@iki.fi>
Date: Sat, 6 Jul 2024 23:17:35 +0000
Subject: [PATCH] fix(lru): don't clear an already cached key on set

---
 internal/lrucache.js      |  4 ++--
 test/internal/lrucache.js | 22 ++++++++++++++++++++++
 2 files changed, 24 insertions(+), 2 deletions(-)

diff --git a/internal/lrucache.js b/internal/lrucache.js
index 6d89ec94..7216e48e 100644
--- a/internal/lrucache.js
+++ b/internal/lrucache.js
@@ -21,9 +21,9 @@ class LRUCache {
   }
 
   set (key, value) {
-    const deleted = this.delete(key)
+    this.delete(key)
 
-    if (!deleted && value !== undefined) {
+    if (value !== undefined) {
       // If cache is full, delete the least recently used item
       if (this.map.size >= this.max) {
         const firstKey = this.map.keys().next().value
diff --git a/test/internal/lrucache.js b/test/internal/lrucache.js
index 83a0e797..0e2cb3d8 100644
--- a/test/internal/lrucache.js
+++ b/test/internal/lrucache.js
@@ -17,3 +17,25 @@ test('basic cache operation', t => {
   c.set(42, undefined)
   t.end()
 })
+
+test('test setting the same key twice', t => {
+  const c = new LRUCache()
+  c.set(1, 1)
+  c.set(1, 2)
+  t.equal(c.get(1), 2)
+  t.end()
+})
+
+test('test that setting an already cached key bumps it last in the LRU queue', t => {
+  const c = new LRUCache()
+  const max = 1000
+
+  for (let i = 0; i < max; i++) {
+    c.set(i, i)
+  }
+  c.set(0, 0)
+  c.set(1001, 1001)
+  t.equal(c.get(0), 0)
+  t.equal(c.get(1), undefined)
+  t.end()
+})