I think there may be a possible bug on this challenge because my code works well on a different environment. Please help me check it out and tell me what I’m missing so far. Thanks in advance. Here is the challenge link missing letters challenge
function fearNotLetter(str) {
let word = "abcdefghijklmnopqrstuvwxyz";
const start = word.indexOf(str[0]);
const end = word.indexOf(str[str.length - 1]);
let section = word.slice(start, end + 1);
if(section === str) {
return undefined;
}else{
section.split("").map(letter => {
if(str.includes(letter) == false){
return letter;
}
});
}
}