如何使用打字稿和返回字符串创建枚举

Question

guys i wanna ask if i can create an enum that looks like this

export enum CompanyMemberTypeEnum {
    DIRECTORS,
    SHAREHOLDERS,
    DIRECTORS_AND_SHAREHOLDERS
}

CompanyMemberTypeEnum.DIRECTORS will return 0 right ? but how if i want to create a function that can get string of an enum like this

CompanyMemberTypeEnum.getList(CompanyMemberTypeEnum.DIRECTORS)

will return 'Directors'

in a enum file, is that possible ?

Answer 1

Prior to TypeScript 2.4 , TypeScript only supported number-based enums, but nowadays it is possible out of the box.

A SO answer about it has been already provided here as toskv pointed out.

As example:

enum BeerTypes {
   lager = "Lager",
   ipa = "IPA"

};

Answer 2

First, you need to create a base Enum<T> class.

export class Enum<T> {
  public constructor(public readonly value: T) {}
  public toString() {
    return this.value.toString();
  }
}

Create your class that extends Enum<T> ;

export class CompanyMemberTypeEnum extends Enum<string> {
  public static readonly DIRECTORS = new Enum('DIRECTORS');
  public static readonly SHAREHOLDERS= new Enum('SHAREHOLDERS');
  public static readonly DIRECTORS_AND_SHAREHOLDERS = new Enum('DIRECTORS_AND_SHAREHOLDERS');
}

now, you can use your enums like;

console.log(CompanyMemberTypeEnum.DIRECTORS); // Enum { value: 'DIRECTORS' }
console.log(CompanyMemberTypeEnum.DIRECTORS.value); // DIRECTORS
console.log(CompanyMemberTypeEnum.DIRECTORS.toString()); // DIRECTORS

Answer 3

You can define your enum like:

export enum CompanyMemberTypeEnum {
    DIRECTORS = <any>'Directors',
    SHAREHOLDERS = <any>'ShareHolders',
    DIRECTORS_AND_SHAREHOLDERS = <any>'Directors and shareholders'
}