How to represent a middleware that conditionally updates the context or manipulates the response?

[FraBle]

A simple use case would be to validate a user's access from cookie info:

1. Get user auth info from cookies
2. If user is auth'd (checked via async call), add the user details in the context object
3. Else, reset the cookies

Code example:

import type { Get, UniversalMiddleware } from '@universal-middleware/core'
export const middleware = (() => async (request: Request, context: Universal.Context, _runtime) => {
    const user = await validateUser(request)
    if (user) {
        return {
            ...context,
            user
        }
    }
    return (response: Response) => {
        // Logic to reset cookies via `Set-Cookie`
        // ...
        return response;
    };

}) satisfies Get<[], UniversalMiddleware>;

It's basically not possible to combine these two middlewares into one.

This fails with:

Type '(request: Request, context: Context, _runtime: RuntimeAdapter) => Promise<((response: Response) => Response) | { user: any; }>' is not assignable to type 'UniversalMiddleware<Context, Context>'.
  Type 'Promise<((response: Response) => Response) | { user: any; }>' is not assignable to type 'void | Context | Response | Promise<Response | undefined> | Promise<void | undefined> | ((response: Response) => Awaitable<...>) | Promise<...> | undefined'.
    Type 'Promise<((response: Response) => Response) | { user: any; }>' is not assignable to type 'Promise<Response | undefined>'.
      Type '((response: Response) => Response) | { user: any; }' is not assignable to type 'Response | undefined'.
        Type '(response: Response) => Response' is not assignable to type 'Response'.ts(2322)
index.d.ts(72, 36): The expected type comes from the return type of this signature.

[magne4000]

The issue comes from UniversalMiddleware typings definition (that means that it does work at runtime). I'll fix this today.

[magne4000]

Fixed in latest release

[FraBle]

Thank you for such a quick follow-up and turnaround 💯