如何从 Javascript 对象中获取属性值 [英] How to get Property value from a Javascript object

问题描述

我有一个 JavaScript 对象.

I have a JavaScript object.

var obj = { Id: "100", Name: "John", Address: {Id:1,Name:"Bangalore"} }
var dataToRetrieve= "Name";

function GetPropertyValue(object,dataToRetrieve){
      return obj[dataToRetrieve]
}
var retval = GetPropertyValue(obj,dataToRetrieve)

这很好用.但是如果我尝试获取 "Address.Name" 的属性值，

This works fine. But if I try to get the value of property value of "Address.Name" ,

喜欢:var dataToRetrieve = "Address.Name";它显示 undefined.

注意: 属性变量由用户从 HTML 中设置，可以根据用户要求(他想要的属性值)进行更改.

Note : The property variable is set by user from HTML And it can be changed according to user requirement(which property value he wants).

我想要达到的目标:

1) 如果 dataToRetrieve = "Name" ，它应该给我 "John",

1) If dataToRetrieve = "Name" , it should give me "John",

2) 如果 dataToRetrieve = "Id" ，它应该给我 "100",

2) If dataToRetrieve = "Id" , it should give me "100",

3) 如果 dataToRetrieve = "Address.Name" ，它应该给我 "Bangalore",

3) If dataToRetrieve = "Address.Name" , it should give me "Bangalore",

4) 如果 dataToRetrieve = "Address.Id" ，它应该给我 1

4) If dataToRetrieve = "Address.Id" , it should give me 1

Plunkr 在这里:PLUNKR

Plunkr Here : PLUNKR

推荐答案

使用 reduce() 方法

var obj = {
  Id: "100",
  Name: "John",
  Address: {
    Id: 1,
    Name: "Bangalore"
  }
}

function GetPropertyValue(obj1, dataToRetrieve) {
  return dataToRetrieve
    .split('.') // split string based on `.`
    .reduce(function(o, k) {
      return o && o[k]; // get inner property if `o` is defined else get `o` and return
    }, obj1) // set initial value as object
}


console.log(
  GetPropertyValue(obj, "Name"),
  GetPropertyValue(obj, "Id"),
  GetPropertyValue(obj, "Address.Name"),
  GetPropertyValue(obj, "Address.Id"),
  GetPropertyValue(obj, "Address.Idsd"),
  GetPropertyValue(obj, "Addre.Idsd")
)

<小时>对于较旧的浏览器，请检查 reduce 方法的 polyfill 选项.

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