Unable to prolong express request

Question

Unable to prolong express request

Attempting to enhance the Request interface of Express like so:

import express, { Request, Response } from 'express';
interface IRequest extends Request {
  user: {
    id: string;
  }
}

const router = express.Router();

router.get('/', auth, async (req: IRequest, res: Response) => {
  try {
    const user = await User.findById(req.user.id).select('-password');
    res.json(user);
  } catch (e) {
    console.error((e as Error).message);
    res.status(500).send('Server Error');
  }
});

Encountered this error during the process:

No overload matches this call. Overload 1 of 3, '(path: PathParams, ...handlers: RequestHandler<ParamsDictionary, any, any, ParsedQs>[]): Router', gave the following error. Argument of type '(req: IRequest, res: Response) => Promise' is not assignable to parameter of type 'RequestHandler<ParamsDictionary, any, any, ParsedQs>'. Types of parameters 'req' and 'req' are incompatible. Property 'user' is missing in type 'Request<ParamsDictionary, any, any, ParsedQs>' but required in type 'IRequest'. Overload 2 of 3, '(path: PathParams, ...handlers: RequestHandlerParams<ParamsDictionary, any, any, ParsedQs>[]): Router', gave the following error. Argument of type '(req: IRequest, res: Response) => Promise' is not assignable to parameter of type 'RequestHandlerParams<ParamsDictionary, any, any, ParsedQs>'. Type '(req: IRequest, res: Response) => Promise' is not assignable to type 'RequestHandler<ParamsDictionary, any, any, ParsedQs>'.ts(2769)

typescript express typescript-types

Answer 1

Answer №1

When working with Typescript and Express, you may encounter a situation where Typescript assumes the request object emitted by Express to be of type Request instead of IRequest, even if you explicitly define it in your code:

router.get('/', auth, async (req: IRequest, res: Response) => {

To handle this discrepancy, you can utilize declaration merging to enhance Express' internal request object with your custom types:

https://www.typescriptlang.org/docs/handbook/declaration-merging.html

If you prefer not to globally modify the Request type, you can perform a type assertion within your route handler to ensure it is indeed an IRequest:

router.get('/', auth, async (req: request, res: Response) => {
  try {
    assertIRequest(req);
    const user = await User.findById(req.user.id).select('-password');
    res.json(user);
  } catch (e) {
    console.error((e as Error).message);
    res.status(500).send('Server Error');
  }
});

function assertIRequest(req: Request|IRequest): asserts req is IRequest {
  if (!req?.user?.id) throw new Error('Request was not an IRequest');
}

Answer 2

When working with Typescript and Express, you may encounter a situation where Typescript assumes the request object emitted by Express to be of type Request instead of IRequest, even if you explicitly define it in your code:

router.get('/', auth, async (req: IRequest, res: Response) => {

To handle this discrepancy, you can utilize declaration merging to enhance Express' internal request object with your custom types:

https://www.typescriptlang.org/docs/handbook/declaration-merging.html

If you prefer not to globally modify the Request type, you can perform a type assertion within your route handler to ensure it is indeed an IRequest:

router.get('/', auth, async (req: request, res: Response) => {
  try {
    assertIRequest(req);
    const user = await User.findById(req.user.id).select('-password');
    res.json(user);
  } catch (e) {
    console.error((e as Error).message);
    res.status(500).send('Server Error');
  }
});

function assertIRequest(req: Request|IRequest): asserts req is IRequest {
  if (!req?.user?.id) throw new Error('Request was not an IRequest');
}

Answer 3

Answer №2

In the scenario where the interface designated as IRequest serves no other purpose besides what's mentioned above, a helpful guide can be found in this informative blog post by Antonello Zanini. The approach involves extending the express-defined interface by creating a declaration file named src/types/express/index.d.ts, with the necessary content included:

// src/types/express/index.d.ts

// To prevent TypeScript error and designate the file as a module
export {}

declare global {
  namespace Express {
    export interface Request {
      user: {
        id: string;
      }
    }
  }
}

Similar to the method outlined in another response, TypeScript's declaration merging feature will combine the two declarations effectively.

For those seeking insights on a related issue, the delayed provision of this solution may prove beneficial. I encountered a similar conundrum and found assistance through a specific query.

Answer 4

In the scenario where the interface designated as IRequest serves no other purpose besides what's mentioned above, a helpful guide can be found in this informative blog post by Antonello Zanini. The approach involves extending the express-defined interface by creating a declaration file named src/types/express/index.d.ts, with the necessary content included:

// src/types/express/index.d.ts

// To prevent TypeScript error and designate the file as a module
export {}

declare global {
  namespace Express {
    export interface Request {
      user: {
        id: string;
      }
    }
  }
}

Similar to the method outlined in another response, TypeScript's declaration merging feature will combine the two declarations effectively.

For those seeking insights on a related issue, the delayed provision of this solution may prove beneficial. I encountered a similar conundrum and found assistance through a specific query.

Unable to prolong express request

Answer №1

Answer №2

Similar questions

Assign the chosen option in the Angular 2 dropdown menu to a specific value

ExpressJs encounters issue with setting Cookie

`What exactly do auth.guard.ts and the AuthenticationService do in Angular 8?`

Definitions for images in the following format

Jest on Github Actions

Building a framework for combined frontend and backend plugins using Vue and Express

I am having trouble with an undefined variable in my expressjs server.js file. How can I properly reference

How come MongoDB is displaying a circular object despite the fact that the object inserted is not circular in nature?

Guide to incorporating API testing into your Angular application

Can you explain the significance of the syntax provided?

Is there a way to change the data type of all parameters in a function to a specific type?

Ways to align the label at the center of an MUI Textfield

The Express route path could not be retrieved while utilizing node.js and Angular.js

"Integrating React with Express.js: A Step-by-Step

What is the best approach for handling server-side validation errors in Angular when making an HTTP call?

The MongoDB/Express API successfully responds with a status code of 200 but fails to update the entry

Error with Angular Material in version 8.2.14

Issues with typescript compiler when using React-beautiful-dnd

Tips for establishing optimal parameters for an object's dynamic property

What is the best way to extract a value from an input tag within a TSX component and then utilize that value in a Node JS file located in a separate directory?