From 38706cc78c10549b1a8759d5a39a29ef8486c0cb Mon Sep 17 00:00:00 2001
From: Jordan Harband <ljharb@gmail.com>
Date: Thu, 16 Dec 2021 14:39:40 -0800
Subject: [PATCH] util: refactor addNumericSeparator logic

---
 lib/internal/util/inspect.js | 18 ++++++++----------
 1 file changed, 8 insertions(+), 10 deletions(-)

diff --git a/lib/internal/util/inspect.js b/lib/internal/util/inspect.js
index 659fd7b671e742..df0f9b921efb9e 100644
--- a/lib/internal/util/inspect.js
+++ b/lib/internal/util/inspect.js
@@ -1458,15 +1458,11 @@ function handleMaxCallStackSize(ctx, err, constructorName, indentationLvl) {
 }
 
 function addNumericSeparator(integerString) {
-  let result = '';
-  let i = integerString.length;
-  const start = integerString.startsWith('-') ? 1 : 0;
-  for (; i >= start + 4; i -= 3) {
-    result = `_${integerString.slice(i - 3, i)}${result}`;
-  }
-  return i === integerString.length ?
-    integerString :
-    `${integerString.slice(0, i)}${result}`;
+  return StringPrototypeReplace(
+    integerString,
+    /[0-9](?=(?:[0-9]{3})+(?![0-9]))/g,
+    '$&_'
+  );
 }
 
 function addNumericSeparatorEnd(integerString) {
@@ -1502,7 +1498,9 @@ function formatNumber(fn, number, numericSeparator) {
   return fn(`${
     addNumericSeparator(string)
   }.${
-    addNumericSeparatorEnd(String(number).slice(string.length + 1))
+    StringPrototypeSlice(
+      addNumericSeparatorEnd(String(number), string.length + 1)
+    )
   }`, 'number');
 }