binarySearch.js

function binarySearch(arr, value) {
  let leftIndex = 0;
  let rightIndex = arr.length - 1;  

  while(leftIndex <= rightIndex) {
    let middleIndex =  Math.floor((leftIndex + rightIndex)/2);

    if(arr[middleIndex] === value) {
      return middleIndex;
    } else if(arr[middleIndex] < value) {
      leftIndex = middleIndex + 1;
    } else {
      rightIndex = middleIndex - 1;
    }
  }  

  return -1;
}

console.log(binarySearch([2, 8, 10, 14, 33, 61, 117], 117));
console.log(binarySearch([1, 3, 9, 12, 110], 1));
console.log(binarySearch([-5, 1, 4, 332], 4));
console.log(binarySearch([-5, 1, 4, 332], 14));