adamcee / algo-factorial2

Factorial Challenge

Usage

Usage

To run factorial.js itself:

node factorial.js

To run factorialSpec.js:

node factorialSpec.js

In this exercise you are going to create a function that takes a number parameter and returns the factorial of it.

Factorial has a very specific definition. Learn more here. As an overview though, a factorial is the result of multiplying a sequence of descending numbers down to 0. Factorials are only defined for non-negative integer numbers. This definition includes zero. Though 0! is equal to 1, so treat it as an edge case.

factorial(0); // 1
factorial(1); // 1
factorial(2); // 2 * 1
factorial(3); // 3 * 2 * 1
factorial(4); // 4 * 3 * 2 * 1
// ...etc