binarySearch.js

/**
 * Performs a binary search on the provided sorted list and returns the index of the item if found. If it can't be found it'll return -1.
 *
 * @param {*[]} list Items to search through.
 * @param {*} item The item to look for.
 * @return {Number} The index of the item if found, -1 if not.
 */
function binarySearch(list, item) {
    var min = 0;
    var max = list.length - 1;
    var guess;

	var bitwise = (max <= 2147483647) ? true : false;
	if (bitwise) {
		while (min <= max) {
			guess = (min + max) >> 1;
			if (list[guess] === item) { return guess; }
			else {
				if (list[guess] < item) { min = guess + 1; }
				else { max = guess - 1; }
			}
		}
	} else {
		while (min <= max) {
			guess = Math.floor((min + max) / 2);
			if (list[guess] === item) { return guess; }
			else {
				if (list[guess] < item) { min = guess + 1; }
				else { max = guess - 1; }
			}
		}
	}

    return -1;
}

module.exports = binarySearch;