JavaScript: Replace every character in a given string with the character following it in the alphabet

JavaScript Basic: Exercise-49 with Solution

Write a JavaScript program to replace every character in a given string with the character following it in the alphabet. Convert vowels to uppercase.

This JavaScript program replaces each character in a string with the next character in the alphabet, and converts vowels to uppercase. It iterates through the string, modifies each character accordingly, and then constructs the new modified string.

Visual Presentation:

Sample Solution:

JavaScript Code:

// Define a function named LetterChanges with parameter text
function LetterChanges(text) {
    // Initialize an array by splitting the input text into individual characters
    var s = text.split('');

    // Iterate through each character in the array
    for (var i = 0; i < s.length; i++) {
        // Caesar cipher: Shift each character by one position in the alphabet
        switch(s[i]) {
            case ' ':
                break;
            case 'z':
                s[i] = 'a';
                break;
            case 'Z': 
                s[i] = 'A';
                break;
            default:
                s[i] = String.fromCharCode(1 + s[i].charCodeAt(0));
        }

        // Convert vowels to uppercase
        switch(s[i]) {
            case 'a': case 'e': case 'i': case 'o': case 'u':
                s[i] = s[i].toUpperCase();
        }
    }

    // Join the modified characters back into a string and return the result
    return s.join('');
}

// Log the result of calling LetterChanges with the argument "PYTHON" to the console
console.log(LetterChanges("PYTHON"));

// Log the result of calling LetterChanges with the argument "W3R" to the console
console.log(LetterChanges("W3R"));

// Log the result of calling LetterChanges with the argument "php" to the console
console.log(LetterChanges("php"));

Output:

QZUIPO
X4S
qIq

Live Demo:

See the Pen JavaScript - Replace every character in a given string with the character following it in the alphabet - basic-ex-49 by w3resource (@w3resource) on CodePen.

Flowchart:

ES6 Version:

// Define a function named LetterChanges with parameter text
const LetterChanges = (text) => {
    // Split the input text into an array of characters
    let s = text.split('');

    // Iterate through each character in the array
    for (let i = 0; i < s.length; i++) {
        // Caesar cipher
        switch (s[i]) {
            case ' ':
                break;
            case 'z':
                s[i] = 'a';
                break;
            case 'Z':
                s[i] = 'A';
                break;
            default:
                s[i] = String.fromCharCode(1 + s[i].charCodeAt(0));
        }

        // Upper-case vowels
        switch (s[i]) {
            case 'a':
            case 'e':
            case 'i':
            case 'o':
            case 'u':
                s[i] = s[i].toUpperCase();
        }
    }

    // Join the modified array back into a string and return it
    return s.join('');
};

// Log the result of calling LetterChanges with the argument "PYTHON" to the console
console.log(LetterChanges("PYTHON"));

// Log the result of calling LetterChanges with the argument "W3R" to the console
console.log(LetterChanges("W3R"));

// Log the result of calling LetterChanges with the argument "php" to the console
console.log(LetterChanges("php"));

Improve this sample solution and post your code through Disqus.

Previous: JavaScript program to reverse a given string.
Next: JavaScript program to capitalize the first letter of each word of a given string.