Question

我有以下代码，该代码使用JavaScript中的2个对象数组并进行比较并合并内容，返回第一个数组中的所有对象，以及第二个对象中ID不在第一个数组中的所有对象。 / p>

但是对于那些来自第二个数组的项目，我想修改它在新数组中的条目，使其仅包含某些属性（例如id和make），并添加一个新的占位符属性（例如，键入：“ car ”）。我相信它将使用map函数，但是我似乎无法使其正常工作。

    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);

我希望组合的数组以以下内容结尾：

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"},
];

但是它最终以：

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

Answer 1

在.map中，应提取id和make属性，并返回一个对象，该对象仅包含这些属性以及type的{{1}}：

car

Answer 2

您应该更改地图功能这是代码。仅有car2的地图功能正在更改

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(car2 => {
              //add new prop type to car
              const tempCar2 = Object.assign(car2,{type:"car"});
              //remove year and model
              delete tempCar2.year                    
              delete tempCar2.model
              return tempCar2;
            //Object.assign(car2, { id: car2.id });
          })
      ];
      combined.sort(({ id: aId }, { id: bId }) => aId - bId);
      console.log(combined);

使用过滤器和映射修改合并数组

2 个答案: