From 88a0bb0685175b2b8ae14e3c4a3e9db1604dfd09 Mon Sep 17 00:00:00 2001
From: Christophe Diederichs <chm-diederichs@protonmail.com>
Date: Wed, 30 Oct 2024 10:30:46 +0000
Subject: [PATCH] missing helper

---
 lib/memory-overlay.js | 15 ++++++++++++---
 1 file changed, 12 insertions(+), 3 deletions(-)

diff --git a/lib/memory-overlay.js b/lib/memory-overlay.js
index a1b0716..41bb34b 100644
--- a/lib/memory-overlay.js
+++ b/lib/memory-overlay.js
@@ -62,11 +62,9 @@ class MemoryOverlay {
 
   async peekLastTreeNode () {
     const mem = this.treeNodes === null ? null : findHighest(this.treeNodes)
-
-    const node = mem.valid ? mem.value : null
     const disk = await this.storage.peekLastTreeNode()
 
-    return (node && (!disk || node.index > disk.index)) ? node : disk
+    return (mem && (!disk || mem.index > disk.index)) ? mem : disk
   }
 
   async peekLastBitfieldPage () {
@@ -273,6 +271,17 @@ class MemoryOverlayWriteBatch {
   }
 }
 
+function findHighest (map) {
+  let node = null
+
+  for (const t of map.values()) {
+    if (node && t.index < node.index) continue
+    node = t
+  }
+
+  return node
+}
+
 function mergeMap (a, b) {
   if (a === null) return b
   for (const [key, value] of b) a.set(key, value)