Binary Search

Given an array of integers nums which is sorted in ascending order, and an integer target, write a function to search target in nums. If target exists, then return its index. Otherwise, return -1. You must write an algorithm with O(log n) runtime complexity.

Example 1:
Input: nums = [-1,0,3,5,9,12], target = 9
Output: 4

Example 2:
Input: nums = [-1,0,3,5,9,12], target = 2
Output: -1

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

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

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

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

    return -1;
}