Fast pow() vs. slow pow()

index.js

const fastPow = (x, n) => {
  if (x <= 0) return 0;
  if (n === 0) return 1;
  if (n === 1) return x;
  
  const result = fastPow(x, n >> 1);
  
  return (n & 1) ? result * x : result;
};

const slowPow = (x, n) => {
  if (x <= 0) return 0;
  
  let result = 1;
  for (let i = 0; i < n; ++i) {
    result *= x;
  }
  return result;
};