Argument of type import().Client is not assignable to parameter of type import().Client

Question

I have two modules:

In one module I reference a function from another module run:

@myorg/server

import { Client } from '.'
import { Middleware } from '@myorg/middleware'

let client = new Client()
Middleware.run(client)

Then in the other module I reference only a type like this:

@myorg/middleware

// References a '.d.ts' file
import { Client } from '@myorg/server'

export class Middleware {

  public run(client: Client){
    // Do some stuff
  }

}

When I have this setup, Middleware.run(client) gives me the following error:

Argument of type 'import("/framework/server/src/Client").Client' is not assignable to parameter of type 'import("/framework/server/types/Client").Client'.

As the error points out src (the actual code) and types (the .d.ts file) are not compatible. What is causing this and how can I fix it?

Answer 1

You should also import the type Client in @myorg/middleware from the same source file that @myorg/server imports it from.

Explanation: In @myorg/middleware you are importing the type Client from a type declaration file (.d.ts) which I assume you have referenced it on top of the file with a /// directive. Whereas in the @myorg/server that Client type is directly imported from the actual source code. Therefore Typescript does not consider those two as the same and that's why you get this error.