Get a parameter value from a GET request url. "TypeError: Cannot read property"

Question

我只是想从 get 请求的 url 路由参数中获取数据。我很确定我以前有这个工作，而且我没有改变任何东西。不确定发生了什么。

我一直在整个代码中调用 console.log，只是想看看会出现什么。但他们甚至从未被召唤过。仅显示错误消息。

我正在使用邮递员，这是我正在发出的获取请求：

http://localhost:3333/users/accountidfind/1

这是我的 index.ts 文件中的路由器：

app.use('/users', userRouter);

这是错误来源的代码段：

userRouter.get('/accountidfind/:account_id', async (req: Request, resp: Response) => {
  //console.log(`retrieving user with id ${(<any>+req).params.account_id}`);
  const account_id = (<any>+req).params.account_id;

这是整个代码：

import { Request, Response } from "express";
      import * as express from "express";
      import * as userDao from "../dao/user-dao";
      
userRouter.get('/accountidfind/:account_id', async (req: Request, resp: Response) => {
      //console.log(`retrieving user with id ${(<any>+req).params.account_id}`);
      const account_id = (<any>+req).params.account_id;
      
      try {
        const user = await userDao.getUserById(account_id);
        if (user !== undefined) {
          resp.json(user);
        } else {
          resp.sendStatus(400);
        }
      } catch (err) {
        resp.sendStatus(500);
      }
    });

这是我遇到的错误：

 (node:9532) UnhandledPromiseRejectionWarning: TypeError: Cannot read property 'account_id' of undefined
    at C:\GitFolder\roqq\server\routers\user-router.ts:95:41
    at Generator.next (<anonymous>)
    at C:\GitFolder\roqq\server\routers\user-router.ts:27:71
    at new Promise (<anonymous>)
    at __awaiter (C:\GitFolder\roqq\server\routers\user-router.ts:23:12)
    at C:\GitFolder\roqq\server\routers\user-router.ts:94:85
    at Layer.handle [as handle_request] (C:\GitFolder\roqq\server\node_modules\express\lib\router\layer.js:95:5)
    at next (C:\GitFolder\roqq\server\node_modules\express\lib\router\route.js:137:13)
    at Route.dispatch (C:\GitFolder\roqq\server\node_modules\express\lib\router\route.js:112:3)
    at Layer.handle [as handle_request] (C:\GitFolder\roqq\server\node_modules\express\lib\router\layer.js:95:5)
(node:9532) UnhandledPromiseRejectionWarning: Unhandled promise rejection. This error originated either by throwing inside of an async function without a catch block, or by rejecting a promise which was not handled with .catch(). To terminate the node process on unhandled promise rejection, use the CLI flag `--unhandled-rejections=strict` (see https://nodejs.org/api/cli.html#cli_unhandled_rejections_mode). (rejection id: 6)

我也不明白错误消息是怎么说异步函数没有 catch 块的，而实际上确实有一个 catch 块。

Answer 1

问题是您的转换 (<any>+req) 转换为 (+req) 将 req 解析为数字 - 因此您没有 .params

要解决您的问题，请将 (<any>+req) 替换为 (req as any) 或 (<any>req)

Type Assertion Doc

Get a parameter value from a GET request url. "TypeError: Cannot read property"

Get a parameter value from a GET request url. "TypeError: Cannot read property"

url-parameters

node.js

express

get-request

typescript