핸드폰 번호 가리기

solution1

function solution(phone_number) {
    var answer = '';
    for(let i=0;i<phone_number.length;i++){
        if(i>=phone_number.length-4){
            answer += phone_number[i]
        }
        else{
            answer +="*";
          console.log(answer)
        }
    }
    return answer;
}

solution2

function solution(phone_number){
  let answer = "*".repeat(phone_number.length-4)+phone_number.slice(-4)
  return answer
}

Syntax to Know