如何将具有动态键的对象数组转换为单个对象？

Question

我正在尝试将此对象数组转换为单个对象：

const arr = [
  {day: "15/06/34", id: 40, time: "2000", type: "time"},
  {duration: "240", id: "ZF3P49", name: "Race", title: "First ever"},
  {message: "Try to beat me"},
  {car: "Ferrari", userId: "D0Ek5Y"},
]

我不认为这是this question的副本，因为它仅涵盖了非动态密钥。