在JS中以点表示法作为文本获得JSON值

Question

我有下面的JSON。

​

let carStr = `{
  "_id": "Tesla-200",
  "Design": {
    "Wheel": "Black",
    "Seat": "4",
    "Speed": "200"
  }
}`;
let car = JSON.parse(carStr);


let key = "Design.Wheel";


let keys = key.split(".");
let value = car[keys[0]][keys[1]]; // Need to get this value dynamically rather than hard-coding
console.log(value);

​

键是从另一个部分输入的。如何通过将键"Design.Wheel“作为文本动态传递来获得值"Black”。

Answer 1

如果问题是键字符串的长度是动态的，那么使用reduce并在每个阶段访问该值：

​

let carStr = `{
  "_id": "Tesla-200",
  "Design": {
    "Wheel": "Black",
    "Seat": "4",
    "Speed": "200"
  }
}`;
let car = JSON.parse(carStr);

let key = "Design.Wheel";
let keys = key.split(".");

let value = keys.reduce((a, c) => a[c], car);

console.log(value);

key = "Design.Seat";
keys = key.split(".");

value = keys.reduce((a, c) => a[c], car);

console.log(value);

key = "_id";
keys = key.split(".");

value = keys.reduce((a, c) => a[c], car);

console.log(value);

​

只要您总是从根开始(即第一个属性总是可以像car.prop1一样直接访问)，这就可以工作了。