Code for calculating factorial
5! -> 5*4*3*2*1
Using Loop
function factorial(n) {let res = 1,i;for (let i = 2; i <= n; i++) res *= i;return res;}factorial(5); // 120
Using Recursion
function factorial(n) {if (n <= 1) {return 1;}return n * factorial(n - 1);}factorial(5); // 120