--- id: a302f7aae1aa3152a5b413bc title: Factorialize a Number isRequired: true challengeType: 5 forumTopicId: 16013 --- ## Description <section id='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 <code>n!</code> For example: <code>5! = 1 * 2 * 3 * 4 * 5 = 120</code> Only integers greater than or equal to zero will be supplied to the function. </section> ## Instructions <section id='instructions'> </section> ## Tests <section id='tests'> ```yml tests: - text: <code>factorialize(5)</code> should return a number. testString: assert(typeof factorialize(5) === 'number'); - text: <code>factorialize(5)</code> should return 120. testString: assert(factorialize(5) === 120); - text: <code>factorialize(10)</code> should return 3628800. testString: assert(factorialize(10) === 3628800); - text: <code>factorialize(20)</code> should return 2432902008176640000. testString: assert(factorialize(20) === 2432902008176640000); - text: <code>factorialize(0)</code> should return 1. testString: assert(factorialize(0) === 1); ``` </section> ## Challenge Seed <section id='challengeSeed'> <div id='js-seed'> ```js function factorialize(num) { return num; } factorialize(5); ``` </div> </section> ## Solution <section id='solution'> ```js function factorialize(num) { return num < 1 ? 1 : num * factorialize(num - 1); } factorialize(5); ``` </section>