JavaScript snips

binarySearch.js

function binarySearch (array, matcher) {
	var len = array.length,
		head = 0,
		tail = len - 1,
		offset = got = Math.ceil(tail / 2);
	
	if (offset == tail) {
		return offset;
	}
	
	var m = matcher(array[got]);
	if (m) {
		if (m < 0) {
			return offset + binarySearch(array.slice(offset), matcher);
		} else {
			return head + binarySearch(array.slice(0, offset), matcher);
		}
	} else {
		return got;
	}
}

function compare (referrence, input) {
	return input - referrence;
}

function equalTo (refer) {
	return function (num) {
		return compare(refer, num);
	};
}