The export type of namespace presents the wrong typing alert

[LenChang]

TypeScript Version: 3.7.2

Search Terms:
namespace, typing

Code

type Nullable<T> = T | null

export namespace ProfileFields {
   type name = string;
   type WHYYY = string | null;
   type id = string | null;
  // export type WHYYY = Nullable<string>;
  // export type id = Nullable<string>;
}

export interface Profile {
  name: ProfileFields.name;
  WHYYY: ProfileFields.WHYYY;
  id: ProfileFields.id;
}

export type General = Pick<Profile, 'WHYYY' | 'name' | 'id'>

Expected behavior:

type General = {
WHYYY: ProfileFields.WHHYY
name: ProfileFields.name
id: ProfileFields.id
}

Actual behavior:

type General = {
WHYYY: ProfileFields.WHHYY
name: ProfileFields.name
id: ProfileFields.WHHYY
}

Playground Link: Provided

[RyanCavanaugh]

Two type aliases for the same type are considered interchangeable (because they are), and declaration emit can choose arbitrarily between two equivalent types when finding a name to emit.

[LenChang]

But it make me confused. I adjust the type of WHYYY & id to Nullable, and it make code more readable.

Has any better recommended method to use it ?

[typescript-bot]

This issue has been marked 'Working as Intended' and has seen no recent activity. It has been automatically closed for house-keeping purposes.

[RyanCavanaugh]

#37444 should improve this