Factorial Recursion

Q. Write an algorithm that is the factorial function with recursion.

const factorial = function (x) {
 if (x === 0) return 1;
 else return x * factorial(x-1);
}

console.log(factorial(5)); // should be 120 = 5 * 4 * 3 * 2 * 1

1. If x === 0, return 1.
2. Otherwise, return x * factorial(x-1).

x = 5
? x === 0 // False
5 * factorial(4) 
x = 4
? x === 0 // False
4 * factorial(3)
...
x = 1
? x === 0 // False
1 * factorial(0)
x = 0
? x === 0 // True //1
120 = 5 * 4 * 3 * 2 * 1