← Practice
Strings·easy 10 min 50 XP

Count Vowels

Count vowels (a, e, i, o, u) regardless of letter case.

Examples

  • countVowels("JavaScript") → 3

Constraints

  • Keep the required function name so the tests can find it
  • Return a value instead of only logging it
  • Do not mutate inputs unless the challenge asks you to
Count Vowels · editor

Code runs in an isolated Web Worker with a 3-second timeout — no DOM access, and it can never hang the page.