Count the vowels

TypeScript

Easy

Objective

Write a function that counts & returns the number of vowels in a string

Requirements

The function should be called countVowels
It should take a single string as an argument
Your solution should be implemented in TypeScript

Check your solution

Tests

Function name is countVowels
countVowels("hello world")	Expected:	3
countVowels("Lorem Ipsum Dolor Sit Amet")	Expected:	9
countVowels("The quick brown fox jumps over the lazy dog.")	Expected:	11

Solution

Here's how I would approach this, but keep in mind there might be other ways to solve this problem.

function countVowels (string: string): number {
    // Convert string to lower case
    const stringInLowerCase = string.toLowerCase();

    const vowels = ['a', 'e', 'i', 'o', 'u'];
    let count = 0;

    // Loop through the string
    for(let i = 0; i < stringInLowerCase.length; i++) {

        // Check if the current character is a vowel
        if (vowels.includes(stringInLowerCase[i])) {

            // If it is, increment the count
            count++;
        }
    }

    return count;
}

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