https://programmers.co.kr/learn/courses/30/lessons/12931
function solution(n) { var answer = 0; let numArr = []; while(n > 0) { numArr.push(n % 10); n = Math.floor(n / 10); //소수점 버리기 } const sum = numArr.reduce((prev, cur) => prev + cur); return answer = sum; }