[Algorithms] Binary Search Algorithm using TypeScript

Posted 2020-09-29 Answer1215

(binary search trees) which form the basis of modern databases and immutable data structures. Binary search works very much the way humans intuitively search for a name in a yellow pages directory (if you have ever seen one) or the dictionary.

In this lesson we learn how to implement a Binary Search Algorithm using TypeScript / javascript, and we describe the problem that it solves.

 

function binarySearch(
  array: number[],
  element: number,
  start: number = 0,
  end: number= array.length -1
): number {
  
   if(end < start) {
     return -1;
   }
    
    const middle = Math.floor((start + end) / 2);
  return element === array[middle]
    ? middle
    : element < array[middle]
      ? binarySearch(array, element, start, middle - 1)
      : binarySearch(array, element, middle + 1, end);
}

const unsortedArray = [ 6, 7, 8, 9, 10, 1, 2, 3, 4, 5]

console.log("Index of 4: ", binarySearch(unsortedArray.sort(), 4))
console.log("22 not found: ", binarySearch(unsortedArray.sort(), 22))