javascript - 合并对象数组，修改一些结果条目

Question

我有以下代码，它采用 JavaScript 中的 2 个对象数组并比较它们并合并内容，返回第一个数组中的所有对象，以及第二个中具有不在第一个中的 ID 的所有对象。

但是对于来自第二个数组的那些项目，我想修改它在新数组中的条目以仅包含某些属性(例如，id 和 make)并添加一个新的占位符属性(例如，类型:“car ”)。我相信这会使用 map 功能，但我似乎无法让它工作。

    var cars1 = [
        {id: 1, make: "Ford",  model: "F150",  year: 2002},
        {id: 3, make: "Chevy", model: "Tahoe", year: 2003},
    ];

    var cars2 = [
        {id: 2, make: "Kia",    model: "Optima",  year: 2001},
        {id: 4, make: "Nissan", model: "Sentra",  year: 1982},
    ];

    const cars1IDs = new Set(cars1.map(({ id }) => id));
    const combined = [
      ...cars1,
      ...cars2.filter(({ id }) => !cars1IDs.has(id))
              .map(cars2 => cars2.id)
    ];
    combined.sort(({ id: aId }, {id: bId }) => aId - bId);
    console.log(combined);

我希望组合数组以以下内容结束:

var combined = [
    {id: 1, make: "Ford",   model: "F150",  year: 2002},
    {id: 2, make: "Kia",    type: "car"},
    {id: 3, make: "Chevy",  model: "Tahoe", year: 2003},
    {id: 4, make: "Nissan", type: "car"},
];

但它最终变成了:

var combined = [
    {id: 1, make: "Ford",   model: "F150",  year: 2002},
    {id: 3, make: "Chevy", model: "Tahoe", year: 2003},
    2,
    4
];

Answer 1

在.map , 你应该提取 id和 make属性，并返回一个仅包含这些属性加上 type 的对象的 car :

var cars1 = [
    {id: 1, make: "Ford",  model: "F150",  year: 2002},
    {id: 3, make: "Chevy", model: "Tahoe", year: 2003},
];

var cars2 = [
    {id: 2, make: "Kia",    model: "Optima",  year: 2001},
    {id: 4, make: "Nissan", model: "Sentra",  year: 1982},
];

const cars1IDs = new Set(cars1.map(({ id }) => id));
const combined = [
  ...cars1,
  ...cars2.filter(({ id }) => !cars1IDs.has(id))
          .map(({ id, make }) => ({ id, make, type: 'car' }))
];
combined.sort((a, b) => a.id - b.id);
console.log(combined);