Help needed "Where do i belong"

Code passes some test but not all so if anyone could help? Thanks.

function getIndexToIns(arr, num) {
  // Find my place in this sorted array.
 
  
var sort = arr.sort();
var tp = '';
var i;
for (i = 0; i < sort.length; i++) {
  if(sort[i] < num ){
   tp =  sort.indexOf(sort[i]) + 1;
  }else if(sort[i] == num){
     tp =  sort.indexOf(sort[i]) - 1;
  }
}
  return tp;
}

Rethink your logic here.