From 6157c81f4b28a0448207e0c915e4d218c5fc30c3 Mon Sep 17 00:00:00 2001
From: Ruben Bridgewater <ruben.bridgewater@datadoghq.com>
Date: Mon, 15 Dec 2025 18:18:53 +0100
Subject: [PATCH] assert: use a set instead of an array for faster lookup

This is a very small improvement for error creation.

PR-URL: https://github.com/nodejs/node/pull/61076
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Yagiz Nizipli <yagiz@nizipli.com>
Reviewed-By: Antoine du Hamel <duhamelantoine1995@gmail.com>
---
 lib/internal/assert/assertion_error.js | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/lib/internal/assert/assertion_error.js b/lib/internal/assert/assertion_error.js
index 5c15b96b12..5dbf1e7a34 100644
--- a/lib/internal/assert/assertion_error.js
+++ b/lib/internal/assert/assertion_error.js
@@ -10,6 +10,7 @@ const {
   ObjectDefineProperty,
   ObjectGetPrototypeOf,
   ObjectPrototypeHasOwnProperty,
+  SafeSet,
   String,
   StringPrototypeRepeat,
   StringPrototypeSlice,
@@ -42,7 +43,10 @@ const kReadableOperator = {
 const kMaxShortStringLength = 12;
 const kMaxLongStringLength = 512;
 
-const kMethodsWithCustomMessageDiff = ['deepStrictEqual', 'strictEqual', 'partialDeepStrictEqual'];
+const kMethodsWithCustomMessageDiff = new SafeSet()
+  .add('deepStrictEqual')
+  .add('strictEqual')
+  .add('partialDeepStrictEqual');
 
 function copyError(source) {
   const target = ObjectAssign(
@@ -263,7 +267,7 @@ class AssertionError extends Error {
     if (isErrorStackTraceLimitWritable()) Error.stackTraceLimit = 0;
 
     if (message != null) {
-      if (kMethodsWithCustomMessageDiff.includes(operator)) {
+      if (kMethodsWithCustomMessageDiff.has(operator)) {
         super(createErrDiff(actual, expected, operator, message, diff));
       } else {
         super(String(message));
@@ -283,7 +287,7 @@ class AssertionError extends Error {
         expected = copyError(expected);
       }
 
-      if (kMethodsWithCustomMessageDiff.includes(operator)) {
+      if (kMethodsWithCustomMessageDiff.has(operator)) {
         super(createErrDiff(actual, expected, operator, message, diff));
       } else if (operator === 'notDeepStrictEqual' ||
         operator === 'notStrictEqual') {