We are required to write a JavaScript function that takes in a number. The function should first calculate the factorial of that number and then it should return the sum of the digits of the calculated factorial.
For example −
For the number 6, the factorial will be 720, so the output should be 9
Example
const factorial = (num) => { if (num == 1) return 1; return num * factorial(num-1); }; const sumOfDigits = (num = 1) => { const str = num.toString(); let sum = 0; for (var x = -1; ++x < str.length;) { sum += +str[x]; }; return sum; }; const sumFactorialDigits = num => sumOfDigits(factorial(num)); console.log(sumFactorialDigits(6));
Output
This will produce the following output −
9