Type Errors with `next@12.2.0`

[Paul Molluzzo]

There is a TS error when upgrading next to >=12.2.0:

Type error: Type 'IncomingMessage & { cookies: Partial<{ [key: string]: string; }>; }' is not assignable to type '(IncomingMessage & { cookies?: { [key: string]: string; } | undefined; }) | undefined'.
  Type 'IncomingMessage & { cookies: Partial<{ [key: string]: string; }>; }' is not assignable to type 'IncomingMessage & { cookies?: { [key: string]: string; } | undefined; }'.
    Type 'IncomingMessage & { cookies: Partial<{ [key: string]: string; }>; }' is not assignable to type '{ cookies?: { [key: string]: string; } | undefined; }'.
      Types of property 'cookies' are incompatible.
        Type 'Partial<{ [key: string]: string; }>' is not assignable to type '{ [key: string]: string; }'.
          'string' index signatures are incompatible.
            Type 'string | undefined' is not assignable to type 'string'.
              Type 'undefined' is not assignable to type 'string'.

Next updated their cookies recently, which might be the reason for this: https://nextjs.org/docs/messages/middleware-upgrade-guide#cookies-api-revamped

I believe it stems from this library here:

cookies-next/src/types.ts

Lines 6 to 8 in d87cd88

 req?: IncomingMessage & { 
     cookies?:{ [key: string]: string; } | Partial<{ [key: string]: string}> 
 } 

[Andrei Zanouski]

Did you try to use library in middleware?
cookies-next hasn't supported using in middleware yet.

Please, work with cookies like next.js docs
I will try to add supporting it in next versions

[Paul Molluzzo]

I was trying to use the package to support middleware, yes. I didn't realize there wasn't official support for that use case. 😅

In the meantime I was able to resolve the issue by directly consuming the cookies, and look forward to the update.

Thanks for this package and the detailed reply! 🙌