Write a function that takes a string as input and returns number of vowels in string. For example, if the string is “Hello World!”, the function should return 3.
Write a function called countVowels that takes a string as str in its parameter and returns number of vowels in string.
// Function to count vowels in the string
function countVowels(str) {
str = str.toLowerCase(); // Convert string to lower case
const vowels = ['a', 'e', 'i', 'o', 'u']; // List of vowels
let count = 0; // Declare variable to count number of vowels
for (let i = 0; i < str.length; i++) {
// Checking if vowels include the character at str[i]
if (vowels.includes(str[i])) {
count++;
}
}
return count; // Return the total number of vowels
}
In the countVowels function, first convert str string to lowercase. Declare count variable to store number of vowels in str and declare vowels array of vowels and run a loop for every character in str. Inside the loop check if str[index] contains vowels character if yes increase count variable by one. After the loop finished return count, total number of vowels.