TypeScript:扩展导入的枚举

Question

我可以在单个文件中合并枚举声明，例如

export enum Test {
  value1 = <any>'value1',
  value2 = <any>'value2'
}

export enum Test {
  value3 = <any>'value3'
}

这工作正常，但我的意图是有一个共享枚举，我可以稍后扩展，例如

// test.enum.ts
export enum Test {
  value1 = <any>'value1',
  value2 = <any>'value2'
}

// place-to-extend-enum.ts
import { Test } from './test.enum';

export enum Test {
  value3 = <any>'value3'
}

我得到的是

Individual declarations in merged declaration 'Test' must be all exported or all local.

有没有办法实现预期的行为？

Answer 1

引用https://github.com/Microsoft/TypeScript/pull/6213你可以这样做:

// test.enum.ts
export enum Test {
  value1 = <any>'value1',
  value2 = <any>'value2'
}

// place-to-extend-enum.ts
import { Test } from './test.enum';

declare module './test.enum' {
  export enum Test {
    value3 = <any>'value3'
  }
}

...魔法! ;)