Count Vowels in a String

JavaScript

Technical Specification

Count the number of vowels (a, e, i, o, u) present in a given string.

Input/Output Samples

Input:"happy"

Output:1

Input:"CodeWithHappy"

Output:4

Optimal Logic Path

function countVowels(str) {
  const vowels = "aeiouAEIOU";
  let count = 0;
  for (const ch of str) {
    if (vowels.includes(ch)) count++;
  }
  return count;
}

Architectural Deep-Dive

We scan each character and increment the counter if it is in the defined set of vowels.