Implement a Sorted Index Finder

JavaScript
1

Passed this test but can’t help feeling I cheated by hardcoding the edge cases. Any hints on how to make this better?

function getIndexToIns(arr,num){
  arr.sort((a,b)=>a-b);
  if ((arr.length==0) || (arr[0]>=num)) {
    return 0;
  }
  else if (arr[arr.length-1] < num) {
    return arr.length;
  }
    return arr.findIndex(getIndex(num));
}
console.log(getIndexToIns([20, 3, 5], 19));

function getIndex(num){
  return (numCheck) => num <= numCheck;
}
2

Can you please link to the url of the challenge.

4

Updated with link: https://www.freecodecamp.org/learn/full-stack-developer/lab-sorted-index-finder/lab-sorted-index-finder