From b57fea31046cd542bb54eb1d7a6a8329f6744de9 Mon Sep 17 00:00:00 2001
From: imxyy_soope_ <imxyy1soope1@gmail.com>
Date: Thu, 19 Feb 2026 21:54:49 +0800
Subject: [PATCH] optimize: short-circuit update (//)

---
 nix-js/runtime-ts/src/operators.ts | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/nix-js/runtime-ts/src/operators.ts b/nix-js/runtime-ts/src/operators.ts
index 4f47724..75ab841 100644
--- a/nix-js/runtime-ts/src/operators.ts
+++ b/nix-js/runtime-ts/src/operators.ts
@@ -270,6 +270,12 @@ export const op = {
   update: (a: NixValue, b: NixValue): NixAttrs => {
     const mapA = forceAttrs(a);
     const mapB = forceAttrs(b);
+    if (mapA.size === 0) {
+      return mapB;
+    }
+    if (mapB.size === 0) {
+      return mapA;
+    }
     const result: NixAttrs = new Map(mapA);
     for (const [k, v] of mapB) {
       result.set(k, v);