util: fix -0 formatting when numericSeparator is enabled

watilde · aduh95 · commit 5f7f60ac36dc · 2026-06-18T10:11:22.000+02:00
Signed-off-by: Daijiro Wachi <daijiro.wachi@gmail.com> PR-URL: #63815 Reviewed-By: Luigi Pinca <luigipinca@gmail.com> Reviewed-By: Jordan Harband <ljharb@gmail.com>
diff --git a/lib/internal/util/inspect.js b/lib/internal/util/inspect.js
@@ -2189,11 +2189,12 @@ function addNumericSeparatorEnd(integerString) {
 const remainingText = (remaining) => `... ${remaining} more item${remaining > 1 ? 's' : ''}`;
 
 function formatNumber(fn, number, numericSeparator) {
+  // Format -0 as '-0'. Checking `number === -0` won't distinguish 0 from -0.
+  // String(-0) === '0', so this must be checked before any String() conversion.
+  if (ObjectIs(number, -0)) {
+    return fn('-0', 'number');
+  }
   if (!numericSeparator) {
-    // Format -0 as '-0'. Checking `number === -0` won't distinguish 0 from -0.
-    if (ObjectIs(number, -0)) {
-      return fn('-0', 'number');
-    }
     return fn(`${number}`, 'number');
   }
 
diff --git a/test/parallel/test-util-inspect.js b/test/parallel/test-util-inspect.js
@@ -3793,6 +3793,7 @@ assert.strictEqual(
   assert.strictEqual(util.inspect(NaN), 'NaN');
   assert.strictEqual(util.inspect(Infinity), 'Infinity');
   assert.strictEqual(util.inspect(-Infinity), '-Infinity');
+  assert.strictEqual(util.inspect(-0), '-0');
 
   assert.strictEqual(
     util.inspect(new Float64Array([100_000_000])),
@@ -3824,6 +3825,9 @@ assert.strictEqual(
     '-123_456_789.123_456_78'
   );
 
+  // -0 should be formatted as '-0' even with numericSeparator enabled
+  assert.strictEqual(util.inspect(-0, { numericSeparator: true }), '-0');
+
   // Regression test for https://github.com/nodejs/node/issues/59376
   // numericSeparator should work correctly for negative fractional numbers
   {
