Count the Vowels in a String in JavaScript (Exercise)

The challenge

Write countVowels(text) that returns how many vowels (a, e, i, o, u) are in the text. Count capital letters too.

Example

countVowels("Welcome")  // 3

Try it

Write your answer below, then press Check my answer. Your code runs right here in your browser, and the tests tell you what works.

Your solution

It prints

What the tests check

countVowels("Welcome") gives 3
countVowels("JavaScript") gives 3
countVowels("rhythm") gives 0
countVowels("") gives 0

Hints

Stuck? Open one hint at a time. Try again after each one.

Hint 1

Loop over the characters with for…of.

Hint 2

"aeiou".includes(char.toLowerCase()) tells you if a character is a vowel.

A solution

There’s always more than one right way. Read it, make sure you understand it, then try writing it yourself without looking.

Show one possible solution

Solution

function countVowels(text) {
  let count = 0;
  for (const char of text) {
    if ("aeiou".includes(char.toLowerCase())) count++;
  }
  return count;
}

Learn what you need

This exercise uses what Grade 5: Loops: Doing Things Over and Over teaches. Read those notes first if any of it is new.

Count the vowels in a string