From cc1eae95dcfa0bed24923b1f6a97ff1f8dda61fa Mon Sep 17 00:00:00 2001
From: Ruben Bridgewater <ruben@bridgewater.de>
Date: Sat, 9 Dec 2017 14:13:34 -0200
Subject: [PATCH] assert: improve error check

Minor performance improvement.
---
 lib/internal/errors.js | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/lib/internal/errors.js b/lib/internal/errors.js
index 9816474d7a067a..69d506893efa80 100644
--- a/lib/internal/errors.js
+++ b/lib/internal/errors.js
@@ -342,11 +342,14 @@ class AssertionError extends Error {
         red = '\u001b[31m';
       }
       const util = lazyUtil();
-
-      if (actual && actual.stack && actual instanceof Error)
+      if (typeof actual === 'object' && actual !== null &&
+        'stack' in actual && actual instanceof Error) {
         actual = `${actual.name}: ${actual.message}`;
-      if (expected && expected.stack && expected instanceof Error)
+      }
+      if (typeof expected === 'object' && expected !== null &&
+        'stack' in expected && expected instanceof Error) {
         expected = `${expected.name}: ${expected.message}`;
+      }
 
       if (errorDiff === 0) {
         let res = util.inspect(actual);