[배열] 10보다 큰 숫자의 갯수를 반환하는 함수

숫자배열이 주어졌을 때 10보다 큰 숫자의 갯수를 반환하는 함수를 만들어보자.

 

1. forEach

function countBiggerThanTen(numbers) {
  let count = 0;
  numbers.forEach(n => {
    if (n > 10) {
      count++;
    }
  });
  return count;
}
const count = countBiggerThanTen([1, 2, 3, 5, 10, 20, 30, 40, 50, 60]);
console.log(count);

---

2. filter

function countBiggerThanTen(numbers) {
  return numbers.filter(n => n > 10).length;
}
const count = countBiggerThanTen([1, 2, 3, 5, 10, 20, 30, 40, 50, 60]);
console.log(count);

---

3. reduce

function countBiggerThanTen(numbers) {
  return numbers.reduce((acc, current) => {
    if (current > 10) {
      return acc + 1;
    } else{
      return acc;
    }
  }, 0)
}
const count = countBiggerThanTen([1, 2, 3, 5, 10, 20, 30, 40, 50, 60]);
console.log(count);   // 5