--- id: a302f7aae1aa3152a5b413bc title: Factorialize a Number challengeType: 5 forumTopicId: 16013 dashedName: factorialize-a-number --- # --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. ```js assert(typeof factorialize(5) === 'number'); ``` `factorialize(5)` should return 120. ```js assert(factorialize(5) === 120); ``` `factorialize(10)` should return 3628800. ```js assert(factorialize(10) === 3628800); ``` `factorialize(20)` should return 2432902008176640000. ```js assert(factorialize(20) === 2432902008176640000); ``` `factorialize(0)` should return 1. ```js assert(factorialize(0) === 1); ``` # --seed-- ## --seed-contents-- ```js function factorialize(num) { return num; } factorialize(5); ``` # --solutions-- ```js function factorialize(num) { return num < 1 ? 1 : num * factorialize(num - 1); } factorialize(5); ```