From 4eb194a2b10194f3ac1a4c8914d725aa90da265e Mon Sep 17 00:00:00 2001
From: Kunal Pathak <Kunal.Pathak@microsoft.com>
Date: Tue, 14 Mar 2017 17:48:28 -0700
Subject: [PATCH] lib: Use regex to compare error message

To make node engine agnostic, use better comparison method for error
message.

Lazily populate the `circular reference` error message thrown
by `JSON.stringify()` which can be used to compare the error
message thrown.

PR-URL: https://github.com/nodejs/node/pull/11854
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Sakthipriyan Vairamani <thechargingvolcano@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Brian White <mscdex@mscdex.net>
---
 lib/util.js | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/lib/util.js b/lib/util.js
index b243c81dd50..80195c26722 100644
--- a/lib/util.js
+++ b/lib/util.js
@@ -38,14 +38,21 @@ const inspectDefaultOptions = Object.seal({
   breakLength: 60
 });
 
-const CIRCULAR_ERROR_MESSAGE = 'Converting circular structure to JSON';
-
+var CIRCULAR_ERROR_MESSAGE;
 var Debug;
 
 function tryStringify(arg) {
   try {
     return JSON.stringify(arg);
   } catch (err) {
+    // Populate the circular error message lazily
+    if (!CIRCULAR_ERROR_MESSAGE) {
+      try {
+        const a = {}; a.a = a; JSON.stringify(a);
+      } catch (err) {
+        CIRCULAR_ERROR_MESSAGE = err.message;
+      }
+    }
     if (err.name === 'TypeError' && err.message === CIRCULAR_ERROR_MESSAGE)
       return '[Circular]';
     throw err;