isPowerOfTwo
Returns true if the given number is a power of 2, false otherwise.
Use the bitwise binary AND operator (&) to determine if n is a power of 2.
Additionally, check that n is not falsy.
const isPowerOfTwo = (n) => !!n && (n & (n - 1)) == 0;
isPowerOfTwo(0); // false
isPowerOfTwo(1); // true
isPowerOfTwo(8); // true