Pimp my code

I guess this works:

---

function combination(n,k){
return factorial(n)/(factorial(k) + factorial(n-k);
}

function factorial(n){
nf = 1;
for (i=1;i<=n;i++){
nf = nf*i;
}
return nf;
}

---

I'm looking for something more like:

---

def combination (n,k)
f = lambda {|x|(1..x).inject(1){|x,y|x*y}}
result f(n)/(f(k)*f(n-k))
end

---

If anyone can use array.reduce in Javascript without it turning into a mess, I would like to know. <_<