typescript - 从 typescript 中的值获取枚举的键

Question

我有以下枚举

export enum Operators {
    Equal = "1",
    NotEqual = "2",
    GreatherOrEqual = "3",
    LessOrEqual = "4",
    Contains = "5",
    Null = "6",
    NotNull = "7",
    Between = "8",
    StartsWith = "9",
    EndsWith = "10"
}

我需要从存储的值中恢复枚举键。我创建了以下内容:

GetEnumTextByValue ( valueOperator: string ): string {
    const values: string[] = Object.values( Operators ).filter( v => v == v );
    const keys: string[] = Object.keys( Operators ).filter( k => k == k );
    const index: number = values.indexOf( valueOperator );
    return keys[ index ];
}

该函数返回我需要的内容，但是有没有更简单的方法来获取 key ？

Answer 1

我将此函数用于任何枚举

export function getEnumKeyByEnumValue(myEnum: any, enumValue: number | string): string {
  let keys = Object.keys(myEnum).filter((x) => myEnum[x] == enumValue);
  return keys.length > 0 ? keys[0] : '';
}

使用 jest 进行测试

describe('enum', () => {
  enum TestEnumWithNumber {
    ZERO
  }

  enum TestEnumWithString {
    ZERO = 'ZERO'
  }

  it('should return correct key when enum has number values', function () {
    const key = getEnumKeyByEnumValue(TestEnumWithNumber, TestEnumWithNumber.ZERO);
    expect(key).toBe('ZERO');
  });

  it('should return correct key when enum has string values', function () {
    const key = getEnumKeyByEnumValue(TestEnumWithString, TestEnumWithString.ZERO);
    expect(key).toBe('ZERO');
  });
});