Question

我有一个这样的对象。

var myObj = {
  "name":"John",
  "age":30,
  "cars": {
    "car1":"Ford",
    "car2":"BMW",
    "car3":"Fiat"
  }
}

我知道要添加这样的条目。

myObj['model']='XUV';

但是我想在cars对象中添加一个条目（将新的“ Audi”汽车添加为car4）你能告诉我如何添加吗？

最终输出应该像。

 var myObj = {
      "name":"John",
      "age":30,
      "cars": {
        "car1":"Ford",
        "car2":"BMW",
        "car3":"Fiat",
        "car4":"Audi"
      }

}

Answer 1

只是

myObj.cars["car4"] = "Audi";

Answer 2

您需要先访问cars对象，然后在其中分配一个新的key-value，因此请使用myObj.cars.car4 = 'Audi'或与[]即myObj.cars['car4'] = 'Audi'一起使用。

var myObj = {
  "name":"John",
  "age":30,
  "cars": {
    "car1":"Ford",
    "car2":"BMW",
    "car3":"Fiat"
  }
}
myObj.cars.car4 = 'Audi';
console.log(myObj);

Answer 3

2017年答案：Object.assign（）

var obj = {
  "name":"John",
  "age":30,
  "cars": {
    "car1":"Ford",
    "car2":"BMW",
    "car3":"Fiat"
  }
};

Object.assign(obj.cars, {car4: "Audi"});

2018对象传播算子{...}

var obj = {
      "name":"John",
      "age":30,
      "cars": {
        "car1":"Ford",
        "car2":"BMW",
        "car3":"Fiat"
      }
    };

obj.cars = { ...obj.cars, car4: "Audi" }

Answer 4

在我看来，这是一个错误构建的JSON。我将使用数组而不是命名属性"car" + someIndex

var myObj =
{
    "name":"John",
    "age":30,
    "cars": [
        { "brand":"Ford" },
        { "brand":"BMW" },
        { "brand":"Fiat" }
    ]
}
myObj.cars.push({ "brand":"Renault" });
console.log(myObj);

Answer 5

您可以通过多种方式向属性添加新属性

myObj['cars']['car4'] = 'Audi';
myObj['cars'].car4 = 'Audi';
myObj.cars['car4'] = 'Audi';
myObj.cars.car4 = 'Audi';
Object.assign（）：

Object.assign(myObj.cars, {car4: 'Audi'});
新的ECMA 7扩展运算符（...）：

myObj.cars = { ...myObj.cars, car4: 'Audi' }
使用Lodash _ = require('lodash')：

_.set(myObj, ['cars', 'car4'], 'Audi');

lodash.js也可以创建新属性的属性：

_.set(myObj, ['newProp', 'newCar', 'newBrand'], 'Think');

如何将值推入对象

5 个答案: