Recursion question

Question

Why is the answer to this challenge = 8?

function p(a, b) {
if(b == 1)
return a;
else
return a * p(a, --b);
}

console.log(p(2, 3));

I used the online visualise tool and understood the code up till step 8, when p(2, 1) and b == 1 so it returns a, which is 2. but then it returns 4 and then returns 8.

Please help

Answer 1

Wow, thanks a lot. You couldn't have answered it any better.

Answer 2

p is basically recursively defining the power function.

It does this by satisfying the following identities:
a^1=a
a^n=a*(a^[n-1])

Therefore, p(2,3)=2^3=8