109. implement `Math.pow()`

Can you write your own Math.pow() ? The power would only be integers.

pow(1, 2)
// 1

pow(2, 10)
// 1024

pow(4, -1)
// 0.25

All inputs are safe.

Follow-up

You can easily solve this problem by multiplying the base one after another, but it is slow. For power of n, it is needed to do the multiplication n times, can you think of a faster solution ?