Knowing when a recursion tree is finished

gistfile1.js

var functionThatCallsItselfMultipleTimes = function(starting_number) {
	if (starting_number === 1) {
		console.log("THING DONE!")
	} else {
		var roughly_half_the_number = Math.floor(starting_number / 2)
		functionThatCallsItselfMultipleTimes(starting_number - roughly_half_the_number)
		functionThatCallsItselfMultipleTimes(roughly_half_the_number)					
	}
}

functionThatCallsItselfMultipleTimes(7)

console.log("The recursive function was just called.")

var wrapUpRecursiveFunction = function(fun, cb) {
	var running = 0
	return function() {
		running++
		fun.apply(this, Array.prototype.slice.call(arguments))
		running--
		if (running === 0) {
			cb()
		}
	}
}

var callThisAfterAllTheRecursionIsDone = function() {
	console.log("All things done!")
}

functionThatCallsItselfMultipleTimes = wrapUpRecursiveFunction(functionThatCallsItselfMultipleTimes, 
	callThisAfterAllTheRecursionIsDone)

functionThatCallsItselfMultipleTimes(9)