function find(needle, haystack) {

  var minIndex = 0;
  var maxIndex = this.length - 1;
  var currentIndex;
  var currentElement

  while(minIndex <= maxIndex) {
    currentIndex = (minIndex + maxIndex) / 2 | 0;
    currentElement = this[currentIndex];

    if(currentElement < searchElement) {
      minIndex = currentIndex + 1;
    }
    else if (currentElement > searchElement) {
      maxIndex = currentIndex - 1;
    }
    else {
      return currentIndex;
    }
  }
  return -1;
}