function caesarCipher(s, k) {
    // Write your code here
    const alphabet = Array.from('abcdefghijklmnopqrstuvwxyz');
    const upAlphabet = Array.from('abcdefghijklmnopqrstuvwxyz'.toUpperCase());
    let l = []
    const arr = Array.from(s)
    const f = k%26
    arr.forEach(char => {
        const isLetter = alphabet.includes(char) || upAlphabet.includes(char)
        const al = alphabet.includes(char) && isLetter ? alphabet : upAlphabet; 
        if (isLetter) {
            const index = al.indexOf(char);
            if (index + k > al.length) {
                const dex = index + f >= al.length ? (index + f) - al.length : index + f
                l.push(al[dex])
            } else if (index + k == al.length) {
                l.push(al[0])
            } else {
                l.push(al[index + f])
            } 
        } else {
            l.push(char)
        }
    })
    return l.join('');
}