typescript 枚举对象的属性
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Enumerate properties on an object
提问by George Edwards
Given the following class, how can I enumerate its properties, i.e. get an output like [station1, station2, station3 ...]?
给定以下类，我如何枚举其属性，即获得类似的输出[station1, station2, station3 ...]？
I can only see how to enumerate the values of the properties, i.e. [null, null, null].
我只能看到如何枚举属性的值，即[null, null, null].
class stationGuide {
station1: any;
station2: any;
station3: any;
constructor(){
this.station1 = null;
this.station2 = null;
this.station3 = null;
}
}
回答by Nitzan Tomer
You have two options, using the Object.keys()and then forEach, or use for/in:
您有两个选择，使用Object.keys()然后使用 forEach，或者使用for/in：
class stationGuide {
station1: any;
station2: any;
station3: any;
constructor(){
this.station1 = null;
this.station2 = null;
this.station3 = null;
}
}
let a = new stationGuide();
Object.keys(a).forEach(key => console.log(key));
for (let key in a) {
console.log(key);
}
（操场上的代码）
回答by szuuuken
With the Reflectobject you are able to to access and modify any object programmatically. This approach also doesn't throw a "Element implicitly has an 'any' type because expression of type 'string' can't be used to index type '{}'" error.
使用Reflect对象，您可以以编程方式访问和修改任何对象。这种方法也不会抛出“元素隐式具有 'any' 类型，因为类型 'string' 的表达式不能用于索引类型 '{}'”错误。
class Cat {
name: string
age: number
constructor(name: string, age: number){
this.name = name
this.age = age
}
}
function printObject(obj: any):void{
const keys = Object.keys(obj)
const values = keys.map(key => `${key}: ${Reflect.get(obj,key)}`)
console.log(values)
}
const cat = new Cat("Fluffy", 5)
const dog = {
name: "Charlie",
age: 12,
weight: 20
}
printObject(cat)
printObject(dog)
（操场上的代码）
