javascript - 检查两个数组中属性的相同值的快速方法？

Question

我必须找到一种方法来检查两个数组中属性的相同值。

这里有两个包含对象的数组。

// carArray1

[
 { id: 1, driver: "Mario", carName: "Ferrari 488" },
 { id: 2, driver: "Solid Snake", carName: "Prious" },
 { id: 3, driver: "Link", carName: "Explorer" },
 { id: 4, driver: "Zelda", carName: "Genesis" },
 { id: 5, driver: "Ryu", carName: "Range Rover" }
]

// carArray2

[
 { id: 6, driver: "Chun-Li", carName: "Lamborghini" },
 { id: 7, driver: "Blanca", carName: "Camry" },
 { id: 3, driver: "Link", carName: "Explorer" },
 { id: 9, driver: "Kurby", carName: "Ferrari 911" },
 { id: 1, driver: "Mario", carName: "Ferrari 488" },
]

如您所见，carArray1 和 carArray2 都包含相同的对象 ID 1 和 3。

我正在考虑使用map方法迭代carArray2数组

carArray1.map(car1 => 
  carArray2.map(car2 => 
   car1.id === car2.id ? console.log("same property!") : '')
 )

我可以期待“相同的属性(property)!”在控制台中显示两次消息，但我想在不使用双循环的情况下实现它。

Answer 1

要快速完成此操作(O(n) 时间)，首先迭代其中一个数组并将 id 放入 Set 中，然后迭代第二个数组并检查该数组的 ID 是否为当前对象在集合中:

const arr1 = [
 { id: 1, driver: "Mario", carName: "Ferrari 488" },
 { id: 2, driver: "Solid Snake", carName: "Prious" },
 { id: 3, driver: "Link", carName: "Explorer" },
 { id: 4, driver: "Zelda", carName: "Genesis" },
 { id: 5, driver: "Ryu", carName: "Range Rover" }
];

const arr2 = [
 { id: 6, driver: "Chun-Li", carName: "Lamborghini" },
 { id: 7, driver: "Blanca", carName: "Camry" },
 { id: 3, driver: "Link", carName: "Explorer" },
 { id: 9, driver: "Kurby", carName: "Ferrari 911" },
 { id: 1, driver: "Mario", carName: "Ferrari 488" },
];

const arr1Ids = new Set(arr1.map(({ id }) => id));
arr2.forEach(({ id }) => {
  if (arr1Ids.has(id)) {
    console.log('duplicate id:', id);
  }
});