mathball/lib/factorial/index.js

A JavaScript library for Competitive Programming

'use strict';

/* Factorial of a Number
 * Function: factorial()
 */

var validate = require('../validation/non-negative-integer');

/**
 *
 * @param {number} number
 * @returns {number}
 */
function factorial(number) {
  var i = 1,
      result = 1;
  for (; i <= number; i++) {
    result = result * i;
  }
  return result;
}

exports.find = function (num) {
  validate(num, 'factorial');
  return factorial(num);
};