Search a number in an array using Binary Search iteratively (JavaScript)

binary_search_iterative.js

var numList = [1, 2, 3, 4, 5, 6, 7, 8, 9];
var NOT_FOUND = -1;
var NOT_SORTED = -2;

function search(list, num) {
    var start = 0;
    var end = list.length - 1;

    while (true) {
        if (start === end && list[start] !== num) {
            return NOT_FOUND;
        }

        if (list[start] > list[end]) {
            // array is not sorted
            returh NOT_SORTED;
        }

        var center = Math.floor((start + end) / 2);

        if (list[center] === num) {
            return center;
        } else if (num < list[center]) {
            end = center - 1;
        } else {
            start = center + 1;
        }
    }
}

console.log(search(numList, 3));
console.log(search(numList, 9));
console.log(search(numList, 12));