util: fix scientific notation formatting

watilde · aduh95 · commit 60e83d9bfd87 · 2026-06-18T10:11:23.000+02:00
Signed-off-by: Daijiro Wachi <daijiro.wachi@gmail.com> PR-URL: #63823 Reviewed-By: Antoine du Hamel <duhamelantoine1995@gmail.com> 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
@@ -2207,7 +2207,7 @@ function formatNumber(fn, number, numericSeparator) {
     }
     return fn(addNumericSeparator(numberString), 'number');
   }
-  if (NumberIsNaN(number)) {
+  if (NumberIsNaN(number) || StringPrototypeIncludes(numberString, 'e')) {
     return fn(numberString, 'number');
   }
 
diff --git a/test/parallel/test-util-inspect.js b/test/parallel/test-util-inspect.js
@@ -3848,6 +3848,12 @@ assert.strictEqual(
       '-0.123_45'
     );
   }
+
+  // Numbers in scientific notation should not get malformed separators
+  assert.strictEqual(util.inspect(1e-7, { numericSeparator: true }), '1e-7');
+  assert.strictEqual(util.inspect(1.5e-10, { numericSeparator: true }), '1.5e-10');
+  assert.strictEqual(util.inspect(1.23e-100, { numericSeparator: true }), '1.23e-100');
+  assert.strictEqual(util.inspect(1.23456789e-12, { numericSeparator: true }), '1.23456789e-12');
 }
 
 // Regression test for https://github.com/nodejs/node/issues/41244

Original file line number	Diff line number	Diff line change
`@@ -2207,7 +2207,7 @@ function formatNumber(fn, number, numericSeparator) {`
`2207`	`2207`	`}`
`2208`	`2208`	`return fn(addNumericSeparator(numberString), 'number');`
`2209`	`2209`	`}`
`2210`		`- if (NumberIsNaN(number)) {`
	`2210`	`+ if (NumberIsNaN(number) \|\| StringPrototypeIncludes(numberString, 'e')) {`
`2211`	`2211`	`return fn(numberString, 'number');`
`2212`	`2212`	`}`
`2213`	`2213`
Original file line number	Diff line number	Diff line change
`@@ -3848,6 +3848,12 @@ assert.strictEqual(`
`3848`	`3848`	`'-0.123_45'`
`3849`	`3849`	`);`
`3850`	`3850`	`}`
	`3851`	`+`
	`3852`	`+ // Numbers in scientific notation should not get malformed separators`
	`3853`	`+ assert.strictEqual(util.inspect(1e-7, { numericSeparator: true }), '1e-7');`
	`3854`	`+ assert.strictEqual(util.inspect(1.5e-10, { numericSeparator: true }), '1.5e-10');`
	`3855`	`+ assert.strictEqual(util.inspect(1.23e-100, { numericSeparator: true }), '1.23e-100');`
	`3856`	`+ assert.strictEqual(util.inspect(1.23456789e-12, { numericSeparator: true }), '1.23456789e-12');`
`3851`	`3857`	`}`
`3852`	`3858`
`3853`	`3859`	`// Regression test for https://github.com/nodejs/node/issues/41244`