--description--

Return the factorial of the provided integer.

If the integer is represented with the letter n, a factorial is the product of all positive integers less than or equal to n.

Factorials are often represented with the shorthand notation n!

For example: 5! = 1 * 2 * 3 * 4 * 5 = 120

Only integers greater than or equal to zero will be supplied to the function.

--hints--

factorialize(5) should return a number.

assert.isNumber(factorialize(5));

factorialize(5) should return 120.

assert.strictEqual(factorialize(5), 120);

factorialize(10) should return 3628800.

assert.strictEqual(factorialize(10), 3628800);

factorialize(20) should return 2432902008176640000.

assert.strictEqual(factorialize(20), 2432902008176640000);

factorialize(0) should return 1.

assert.strictEqual(factorialize(0), 1);

--seed--

--seed-contents--

function factorialize(num) {
  return num;
}

factorialize(5);

--solutions--

function factorialize(num) {
  return num < 1 ? 1 : num * factorialize(num - 1);
}

factorialize(5);