Adicione números uniformes recurso js

const recursiveEvenSum = (num, sum = 0) => {
   num = num % 2 === 0 ? num : num - 1;
   if(num){
      return recursiveEvenSum(num - 2, sum+num);
   }
   return sum;
};
console.log(recursiveEvenSum(12));
console.log(recursiveEvenSum(122));
console.log(recursiveEvenSum(23));
console.log(recursiveEvenSum(10));
console.log(recursiveEvenSum(19));
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