How to find factorial using a function with constraints in JavaScript

Question

I am trying to find the factorial of an integer using a function with the following constraint

1<=N<=10

Below is my code but when I execute it I am receiving NaN! Can you please explain and show me where is my mistake. Much appreciated!

const factorial = function (n) {
  if (n >= 1 && n <= 10) {
    return n * factorial(n - 1);
  }
};

console.log(factorial(5));

Answer 1

Try to follow your code step by step and you will find the issue quite easily.

When you don't return anything and you tried to access the returned value you get undefined.

Imagine your type factorial(3)

Your code will run 3 * 2 * undefined

You need to return 1 when n = 1.