如何折叠关键过滤对象的数组？

const orders = [
  { category: 'Electronics', amount: 100 },
  { category: 'Clothing', amount: 50 },
  { category: 'Electronics', amount: 200 },
  { category: 'Clothing', amount: 75 },
  { category: 'Books', amount: 30 }
];

const groupedOrders = orders.reduce((acc, order) => {
  if (!acc[order.category]) {
    acc[order.category] = 0;
  }
  acc[order.category] += order.amount;
  return acc;
}, {});

console.log(groupedOrders);
// 输出: { Electronics: 300, Clothing: 125, Books: 30 }

const groupedOrders = orders.reduce((acc, order) => {
  if (!acc[order.amount]) {
    acc[order.amount] = 0;
  }
  acc[order.amount] += order.amount;
  return acc;
}, {});

console.log(groupedOrders);
// 输出: { 100: 100, 50: 50, 200: 200, 75: 75, 30: 30 }