Examples.js

Maybe(13)
	.bind(a => a * a)
	.bind(log);

isWorthy("Loki")
	.bind(null, () => Just("Vision"))
	.bind(name => log(name, "is worthy"));

function isWorthy(name) {
	return name === "Thor" ? Just(name) : Nothing();
}

function log() {
	console.log.apply(console, arguments);
}

Maybe.js

function Maybe(value) {
	return isNullable(value) ? Nothing() : Just(value);
}

function Just(value) {
	return isMonad(value) ? value : Monad(value, bindJust);
}

function Nothing() {
	return Monad(void 0, bindNothing);
}

function Monad(value, operator) {
	return {
		isMonad: true,
		bind: function(right, left) {
			return operator(value, right, left);
		}
	};
}

function bindJust(value, morphism) {
	return isFunction(morphism) ? Just(morphism(value)) : Just(value);
}

function bindNothing(value, right, morphism) {
	return isFunction(morphism) ? Just(morphism()) : Nothing();
}

function isMonad(value) {
	return value && value.isMonad;
}

function isFunction(value) {
	return value instanceof Function;
}

function isNullable(value) {
	return value === void 0 || value === null;
}