javascript - 如何在两个对象数组中合并具有相同键的属性？

Question

有两个对象数组，其中一些具有相同的键，我想合并第一个数组中的相同键。我已经粘贴了我的代码。我使用了嵌套循环，但性能很差 O(n²)。也许我需要另一种方法来提高性能。(由于某些原因我不能使用 ES6，所以如果是 ES5 方法我将不胜感激。)

var people = [
    {
       id: "001",
       name: "David",
       age: 29
    },
    {
       id: "002",
       name: "Lucia",
       age: 41    
    },
    {
       id: "003",
       name: "Steve",
       age: 18
    }
];

var address = [
    {
        id: "001",
        city: "Barcelona"
    },
    {
        id: "002",
        city: "Paris"
    },
    {

    },
    {
        id: "003",
        city: "Tokyo"
    },
    {
        id: "004",
        city: "Barcelona"
    }
];

---

我的代码

people.forEach(function(item) {
  var id = item.id;
    address.forEach(function(location) {
      if (location.id == id) {
        item.address = location.address
      }
     });
});

---

结果

var people = [
    {
       id: "001",
       name: "David",
       age: 29,
       city: "Barcelona"
    },
    {
       id: "002",
       name: "Lucia",
       age: 41,
       city: "Paris"    
    },
    {
       id: "003",
       name: "Steve",
       age: 18,
       city: "Tokyo"
    }
];

我更喜欢新的 people 数组。

Answer 1

你可以拿一个Map使用所有地址，然后使用 map 的扩展属性映射新对象。

此方法采用address 对象的所有属性。

var people = [{ id: "001", name: "David", age: 29 }, { id: "002", name: "Lucia", age: 41 }, { id: "003", name: "Steve", age: 18 }],
    address = [{ id: "001", city: "Barcelona" }, { id: "002", city: "Paris" }, {}, { id: "003", city: "Tokyo" }, { id: "004", city: "Barcelona" }],
    map = new Map(address.map(o => [o.id, o])),
    result = people.map(o => Object.assign({}, o, map.get(o.id)));

console.log(result);

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