在Typescript中按字符串创建枚举实例

Question

I am trying to extract the enum members of a numeric enum in typescript, but window[name] does return an undefined object.

export enum MyEnum {    
  MemberOne = 0,   
  MemberTwo = 1
}

export class ObjectUtils {
  public static GetEnumMembers(name: string): Array<string> {
    let enumInstance = window[name];

    return Object.keys(enumInstance).map((k: any) => enumInstance[k]).filter((x: any) => typeof (x) == "string");
  }
}

So now I call the GetEnumMembers method like this:

ObjectUtils.GetEnumMembers("MyEnum");

enumInstance results undefined.

edit: I want to return a string array with ["MemberOne", "MemberTwo"]

Answer 1

Exported members won't be added to window unless you add them yourself. You can refactor your code to accept the enum itself instead of the enum name:

export enum MyEnum {    
  MemberOne = 0,   
  MemberTwo = 1
}

// Some other file
import { MyEnum } from "./MyEnum"

class ObjectUtils {
  public static GetEnumMembers(e: {
    [key: string]: any
  }): Array<string> {
    return Object.keys(e).map((k: any) => e[k]).filter((x: any) => typeof (x) == "string");
  }
}

// And use it like:
console.log(ObjectUtils.GetEnumMembers(MyEnum));