[@types/cookie-parser]- cookies of type 'any': unsafe-member-access / unsafe-assignment #68587

Thanks for this - I'm generally new to GitHub / opensource and Typescript. I had tried adding cookies to the index.d.ts file under the secret?: string; but it didn't work: I can see in your issue you have added the req.cookies = Object.create(null) so I am guessing that the Express properties (cookies: any) can't be overridden but the req.cookies in cookie-parser can (if it's added to the library) ?

I wonder if it's possible to add a generic type to the Express Request in [@types/express-serve-static-core] for the cookies so they can be typed as you would with the body?

export interface Request<
    P = ParamsDictionary,
    ResBody = any,
    ReqBody = any,
    ReqQuery = ParsedQs,
    LocalsObj extends Record<string, any> = Record<string, any>,
    Cookies: extends Record<string, any> = Record<string, any>,
> extends http.IncomingMessage, Express.Request {

e.g.

const handler = (req: Request<object, object, { username: string, password: string}, object, object, { jwt: string }>, res: Response) => {
    const { jwt } = req.cookies;
    //...
}

The Request interface defined in the cookie-parser package is an example of module augmentation; it's technically the exact same interface as the Express one. Because of that, I don't think it's possible to give it a narrower type.

It's also not possible to add a generic to it afaik, since that would also conflict with the original type. It would have to be added to the original library defining the Request type, which might cause compatibility problems and likely wouldn't be merged.

It's not very elegant, but imo the best solution is just to add type assertions in your own code.

Brilliant thanks, I think I understand it now. I decided to try the module augmentation approach instead of the as Record<string, string> - I've added a declaration file in my project root and everything works as expected:

/* eslint-disable-next-line @typescript-eslint/no-unused-vars */
import * as express from 'express';

declare module 'express' {
  interface Request {
    cookies?: { [key: string]: string };
  }
}

I'm using the cookies in a few different places, and as I know it's not going to cause any side-effects in my code, I thought it would be a good solution.

I originally thought I had made a mistake with my own project module settings as I tried to declare namespace as in cookie-parser but it didn't work - so it's interesting to see that it is also now declare module! Thank you for sorting this!