Prime digits sum of a number in JavaScript

We are required to write a JavaScript function that takes in a number as the first and the only argument. The function should then sum all the digits of the number that are prime and return the sum as a number.

For example −

If the input number is −

const num = 67867852;

Then the output should be −

const output = 21;

because 7 + 7 + 5 + 2 = 21 −

Example

Following is the code −

const num = 67867852;
const sumPrimeDigits = (num) => {
   const primes = '2357';
   let sum = 0;
   while(num){
      const digit = num % 10;
      if(primes.includes('' + digit)){
         sum += digit;
      };
      num = Math.floor(num / 10);
   };
   return sum;
};
console.log(sumPrimeDigits(num));

Output

Following is the console output −

21