使用Express和打字稿的RESTful服务 - 未定义Response.send（）

Question

出现“this”在express.Response.send（）方法内未定义。有没有办法仍然发送我的路由器的成员？

我-router.ts：

import { Router, Request, Response, NextFunction } from 'express'; 
import { MyTsObject } from "../my-ts-object"; 

export class MyRouter { 
    router: Router; 
    myTsObject: MyTsObject; 

    constructor() { 
     this.myTsObject = new MyTsObject(); 
     this.router = Router(); 
     this.init(); 
    } 

    public getData(req: Request, res: Response, next: NextFunction){ 
     res.send(JSON.stringify(this.myTsObject)); // runtime error here: 
     // TypeError: Cannot read property 'myTsObject' of undefined 
    } 

    init() { 
     this.router.get('/', this.getData); 
    } 
} 

app.ts：

import * as express from 'express'; 
import * as logger from 'morgan'; 
import * as bodyParser from 'body-parser'; 
import { MyRouter } from "./routes/my-router"; 

class App { 
    public express: express.Application; 

    constructor() { 
     this.express = express(); 
     this.middleware(); 
     this.routes(); 
    } 

    private middleware(): void { 
     this.express.use(logger('dev')); 
     this.express.use(bodyParser.json()); 
     this.express.use(bodyParser.urlencoded({ extended: false})); 
    } 

    private routes(): void { 
     this.express.use('/', new MyRouter().router); 
    } 

} 

export default new App().express; 

index.ts：

import * as http from 'http'; 
import * as debug from 'debug'; 

import App from './app'; 

debug('ts-express:server'); 

const port = normalizePort(process.env.PORT || 3000); 
App.set('port', port); 

const server = http.createServer(App); 
server.listen(port); 
server.on('error', onError); 
server.on('listening', onListening); 

.... 

参见运行时的我的router.ts文件当我在浏览器中点击网址时发生的错误。我假设在这个上下文中'this'不是指MyRouter对象。是否还有一种方法可以从send（）方法中获取对myTsObject的引用？有没有更好的方法来做到这一点？

Answer 1

您可以将getData方法的上下文绑定到MyRouter在init方法：

init() { 
    this.router.get('/', this.getData.bind(this)); 
} 

另外，您可以通过一个匿名函数来router.get能实现相同的事情：

init() { 
    this.router.get('/', (req: Request, res: Response, next: NextFunction) => this.getData(req, res, next)); 
}