Binary Search Kata in Javascript

mario.js

function binSearch(arr, toSearch) {
  var lowerBound = 0, upperBound = arr.length -1;
  
  while(true) {
    var index = Math.floor((upperBound - lowerBound) / 2 + lowerBound);
    var current = arr[index];
    
    if(current === toSearch) return index;
    
    if(current > toSearch) {
      upperBound = upperBound - Math.floor((upperBound - lowerBound) / 2)
    }
    
    if(current < toSearch) {
      lowerBound = lowerBound + Math.ceil((upperBound - lowerBound) / 2);
    }
    
    if (upperBound === lowerBound) return -1;
  }
  
  return -1;
}