Where do I belong algorithm not passing, right answer

Hi guys, I’m baffled as to why my code wont pass even though it is logging out the right answer.

I’m using a for in loop which wont pass. But when I use a normal for loop, to achieve the same exact answer, it passes. Any idea why?

Your code so far


function getIndexToIns(arr, num) {
  const target = num;
  arr.push(num);
  arr.sort(sortNumber);

  for (var i in arr) {
    if (arr[i] === target) {
      return i;
    } 
  }
  
}

function sortNumber(a,b) {
    return a - b;
}

getIndexToIns([2, 20, 10], 19);



Your browser information:

Your Browser User Agent is: Mozilla/5.0 (Windows NT 6.1; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/61.0.3163.100 Safari/537.36.

Link to the challenge:
https://www.freecodecamp.org/challenges/where-do-i-belong

Oh wow lol. Such a simple yet sneaky oversight on my part. Thank you very much Randell!