Missing letters failing despite console showing otherwise

Tell us what’s happening:
So the challenge requires a missing letter of an alphabetic sequence to be returned. I’ve tested my solution with all the test input strings, and just before I return the result, I log it to the console, which always shows the correct letter. The line near the end where I enclose it in typical string brackets ("") doesn’t change the console result, nor the returned result, as displayed by all the challenges failing. I know it doesn’t return undefined, and the Get A Hint tab suggests using charCodeAt() somewhere, which I could do, but as of now I am more curious as to why the challenges fail, which according to the console, they do not.

Thank you in advance for any help!

Your code so far

function fearNotLetter(str) {
  let newStr = str;
  newStr = newStr.split("");
  let alpbet = "abcdefghijklmnopqrstuvwxyz";
  alpbet = alpbet.split("");

  let indexStart = alpbet.indexOf(newStr[0]);
  let indexEnd = alpbet.indexOf(newStr[newStr.length-1]);

  let comparator = alpbet.slice(indexStart,indexEnd+1);

  let result = comparator.filter( letter => {
    if (newStr.indexOf(letter)!=-1) {
      return false;
    } else {
      return true;
  result = `"${result}"`; //Challenges still fail if omitted

  return result;


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Link to the challenge:

You should be returning a string with the missing letter. Your function does return a string, but string also has literal double quotes surrounding the letter. So where your function should just be return 'i', it instead returns '"i"'.

Although I thought I had evaded this problem, your comment made me think it through, and by removing the double quotes the problem was solved. Thank you for the advice, Randell!