Simple JS Factorial Calculator

factorial_cache.js

(function () {
  'use strict';
 
  var cache = {};
 
  function factorial(number) {
    var keyResult;
    var cacheKey = number.toString();
    console.log('Calculating factorial for ' + number);
    if (cache[cacheKey]) {
        console.log('Found answer in cache..');
        return cache[cacheKey];
      } else {
        if (number == 0 || number == 1)
          return number
        else {
          keyResult = number + factorial(number - 1)
          cache[cacheKey] = keyResult
        }
        
        return keyResult
      }
  }
 
  factorial(10);
  factorial(5);
  factorial(10);
  factorial(13);
})();