Nearest k / linear search for sorted arrays

function nearestK(k, haystack) {
	var smallestDistance = Infinity, distance, closest;
	for (var i = 0, length = haystack.length; i < length; i++) {
		distance = Math.abs(haystack[i] - k);
		if (distance <= smallestDistance) {
			smallestDistance = distance;
			closest = haystack[i];
		}
		if (haystack[i] > k) {
			break;
		}
	}
	return closest;
}