Big O
    const array = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10];
  
    function binarySearch(array, target) {
      let left = 0;
      let right = array.length - 1;

      while (left <= right) {
        let mid = Math.floor((left + right) / 2);

        if (array[mid] === target) {
          return mid;
        }

        if (array[mid] < target) {
          left = mid + 1;
        } else {
          right = mid - 1;
        }
      }

      return -1;
    }
  
    binarySearch(array, 4);
  

Code?

function binarySearch(array, target) {
  let left = 0;
  let right = array.length - 1;

  while (left <= right) {
    let mid = Math.floor((left + right) / 2);

    if (array[mid] === target) {
      return mid;
    }

    if (array[mid] < target) {
      left = mid + 1;
    } else {
      right = mid - 1;
    }
  }

  return -1;
}