hi,
when i test my code, it’s work but the freecodecamp app say “should return a string”. i don’t understand what is wrong.
function fearNotLetter(str) {
let monIndex = 'abcdefghijklmnopqrstuvwxyz'
let monIndexArray = [...monIndex];
let arrayStr = [...str];
let index = monIndexArray.indexOf(arrayStr[0]);
let newArr = monIndex.slice(index, index+arrayStr.length)
let arrVrai = [...newArr];
let count = 0;
arrVrai.map(function (element){
if (arrayStr.indexOf(element) < 0){
count = 1;
return element;
}
})
if (count == 0){
return undefined;
}
}
fearNotLetter("abcdefghjklmno");
**Your browser information:**
User Agent is: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:94.0) Gecko/20100101 Firefox/94.0
Challenge: Missing letters
Link to the challenge: