Find missing letter in list of alphabets

Question

I am trying to solve the following issue:

Find the missing letter in the passed letter range and return it. If all letters are present in the range, return undefine

Answer 1

This will do what you're looking for:

Hit run and check your console

function missingLetter (str) {
    var alphabet = ("abcdefghijklmnopqrstuvwxyz");
    var first = alphabet.indexOf(str[0]);
    var strIndex = 0;
    var missing;

    for (var i = first ; i < str.length ; i++) {
        if (str[strIndex] === alphabet[i]) {
            strIndex++;
        } else {
            missing = alphabet[i];
        }
    }
    return missing;
}

console.log(missingLetter("abce"));
console.log(missingLetter("bcd"));
console.log(missingLetter("abcdefghjklmno"));
console.log(missingLetter("yz"));