Root calculator using Newton's Method

root.js

function pow( number, degree ) {
	
	var memo = 1;
	
	while( degree-- ) {
		memo *= number;
	}
	
	return memo;
}

function root( number, degree, iterations, guess ) {
	
	//Via Newton's method
	
	if( iterations === 0 ) return guess;
	if( typeof guess !== "number" ) guess = number / 2;
	
	var f = ( pow( guess, degree ) - number );
	var df = ( degree * pow( guess, degree - 1 ) );
		
	return root( number, degree, iterations - 1,
		guess - f / df
	);
	
}

Excited about ES6 having default arguments? function root(number, degree, iterations, guess = number / 2); Already available in coffee... :D

That would be quite nice! But, but, coffeescript.