JavaScript: Count the number of vowels in a given string

JavaScript Basic: Exercise-54 with Solution

Count Vowels in String

Write a JavaScript program to count the number of vowels in a given string.

This JavaScript program counts the number of vowels (a, e, i, o, u) in a given string. It iterates through the string, checks each character to see if it is a vowel, and keeps a running total of the vowels encountered.

Visual Presentation:

Sample Solution:

JavaScript Code:

// Define a function named vowel_Count with parameter str
function vowel_Count(str) {
  // Use regular expression to replace all characters not in 'aeiou' with an empty string
  // and get the length of the resulting string, which is the count of vowels
  return str.replace(/[^aeiou]/g, "").length;
}

// Log the result of calling vowel_Count with the given strings to the console
console.log(vowel_Count("Python"));
console.log(vowel_Count("w3resource.com")); 

Output:

1
5

Live Demo:

See the Pen JavaScript - count the number of vowels in a given string - basic-ex-54 by w3resource (@w3resource) on CodePen.

Flowchart:

ES6 Version:

 // Define a function named vowel_Count with parameter str
const vowel_Count = (str) => {
    // Use regular expression to replace non-vowel characters with an empty string,
    // and then return the length of the resulting string
    return str.replace(/[^aeiou]/g, "").length;
};

// Log the result of calling vowel_Count with the given strings to the console
console.log(vowel_Count("Python"));
console.log(vowel_Count("w3resource.com"));

For more Practice: Solve these Related Problems:

• Write a JavaScript program that counts the total number of vowels in a string, treating both uppercase and lowercase vowels equally.
• Write a JavaScript function that returns an object mapping each vowel to its frequency within the given string.
• Write a JavaScript program that counts vowels in a string using regular expressions without iterating through each character.

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