TypeScript：扩展导入的枚举 [英] TypeScript: extending imported enum

问题描述

  export enum Test {
 value1 =< any> ;'value1'，
 value2 =< any>'value2'
} 
 
 export enum Test {
 value3 =< any>'value3'
} 
  

这工作正常，但我的目的是拥有一个可以延长的共享枚举，例如

  // test.enum.ts 
 export enum Test {
 value1 =< any> ;'value1'，
 value2 =< any>'value2'
} 
 
 // place-to-extend-enum.ts 
 import {Test}来自'./test.enum'; 
 
 export enum Test {
 value3 =< any>'value3'
} 
  

我得到的是

合并声明Test中的个人声明必须全为
导出或全部本地。

有没有办法实现所需的行为？

解决方案

参考 https：// github。 com / Microsoft / TypeScript / pull / 6213 你可以做：

  // test.enum.ts 
 export enum Test {
 value1 =< any>'value1'，
 value2 =< any>'value2'
} 
 
 // place- to-extend-enum.ts 
 import {Test} from'./test.enum'; 
 
声明模块'./test.enum'{
 export enum Test {
 value3 =< any>'value3'
} 
} 
  

...
魔术！ ;）

I can merge enum declarations within a single file e.g.

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

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

This works fine, but my intention is to have a shared enum which I can extend later, e.g.

// 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'
}

What I get is

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

Is there a way to achieve the desired behaviour?

解决方案

In refer to https://github.com/Microsoft/TypeScript/pull/6213 you can do :

// 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'
  }
}

... Magic! ;)

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