9. reduce

arr.reduce((accumulator, currentValue, currentIndex, array) => {
// 리듀서 함수 로직
}, initialValue)

const numbers = [1, 2, 3, 4, 5];
const sum = numbers.reduce((acc, current) => acc + current, 0);
console.log(sum); // 15

const products = [
  { name: '사과', price: 1000 },
  { name: '바나나', price: 1500 },
  { name: '오렌지', price: 2000 }
];
const totalPrice = products.reduce((acc, product) => acc + product.price, 0);
console.log(totalPrice); // 4500

const fruits = ['사과', '바나나', '사과', '오렌지', '바나나'];
const fruitCount = fruits.reduce((acc, fruit) => {
  acc[fruit] = (acc[fruit] || 0) + 1;
  return acc;
}, {});
console.log(fruitCount);
// { '사과': 2, '바나나': 2, '오렌지': 1 }