在Typescript中，从一个声明接口扩展一个类

Question

有没有办法像类一样处理TypeScript声明文件中的接口或变量，以便能够从中扩展一个类？

就像这样：

declare module "tedious" {

   import events = module('events');

   export class Request extends event.EventEmitter {
       constructor (sql: string, callback: Function);
       addParameter(name: string, type: any, value: string):any;
       addOutputParameter(name: string, type: any): any;
       sql:string;
       callback: Function;
   };

}

现在我需要重新定义 EventEmitter 接口，像这样使用我的自定义 EventEmitter 声明。

import events = module('events');

class EventEmitter implements events.NodeEventEmitter{
    addListener(event: string, listener: Function);
    on(event: string, listener: Function): any;
    once(event: string, listener: Function): void;
    removeListener(event: string, listener: Function): void;
    removeAllListener(event: string): void;
    setMaxListeners(n: number): void;
    listeners(event: string): { Function; }[];
    emit(event: string, arg1?: any, arg2?: any): void;
}

export class Request extends EventEmitter {
    constructor (sql: string, callback: Function);
    addParameter(name: string, type: any, value: string):any;
    addOutputParameter(name: string, type: any): any;
    sql:string;
    callback: Function;
};

我需要在我的TypeScript文件中扩展它

import tedious = module('tedious');

class Request extends tedious.Request {
   private _myVar:string; 
   constructor(sql: string, callback: Function){
       super(sql, callback);
   }
}

- discipulus

Answer 1

我不知道2013年的情况，但现在很容易：

/// <reference path="../typings/node/node.d.ts" />
import * as events from "events";

class foo extends events.EventEmitter  {
   constructor() {
      super();
   }

   someFunc() { 
      this.emit('doorbell');
   }
}

我曾经也在寻找答案，最终我弄明白了。

- Garrett Serack

Answer 2

它应该正常工作，例如：

。

// Code in a abc.d.ts 
declare module "tedious" {
   export class Request  {
       constructor (sql: string, callback: Function);
       addParameter(name: string, type: any, value: string):any;
       addOutputParameter(name: string, type: any): any;
       sql:string;
       callback: Function;
   };
}

// Your code: 
///<reference path='abc.d.ts'/>
import tedious = module('tedious');

class Request extends tedious.Request {
   private _myVar:string; 
   constructor(sql: string, callback: Function){
       super(sql, callback);
   }
}

你在文件中放置的任何内容都可以放在 .d.ts 文件中。

试一下

- basarat

---

但这样做我就会错过所有的EventEmitter实现，TypeScript也会抛出一个缺少属性错误。这就是为什么我首先重新定义了NodeJS EventEmmiter类的原因。 - discipulus