Exported type merged with 'export * as namespace...' only exports type meaning.

Joni Katajamäki (@katis)

Previously I liked using TS namespaces and declaration merging for creating FP-style modules, without needing the MyModule.T convention:
export type Foobar = { }

export namespace Foobar {
  export function doStuff(foobar: Foobar) { }
}
import { Foobar } from './Foobar'

Foobar.doStuff(fb)
Namespaces are not really the way to go any more, babel doesn't support them, they probably aren't tree-shakeable etc. But I was hoping that the export * as ns syntax could be > used as a replacement, like this:
export type Foobar = import('./Foobar').Foobar

// Or:
// export type { Foobar } from './Foobar'

export * as Foobar from './Foobar'
This seems to pass the nightly compiler, but the compiler only knows that Foobar is re-exported as a type, not a value. It would be great if the compiler could merge them into a combined value & type like with namespaces.

Originally posted by Joni Katajamäki (@katis) in #4813 (comment)

We have certain projects/modules making heavy use of this pattern. The writing is on the wall though that we're in need of change:

no tree shaking support
eslint warnings by default
no support for re-exports/barrel-exports like modules (aka. TS namespaces since being introduced have not kept apace with module namespaces)

I guess I don't have much to add to this issue, its well described, and our use-case is similar. I just wish I could +1000 it :)

Same here, my case:

export * from './types/index.js';

export {
  RequestContext,
  ResponsePayload,
};

In a:

import { RequestContext,  } from '@ns/package';

Only the options: RequestContext and ResponsePayload are showed, none of the types is present, but it works in runtime.

types/index.js is:

// ...
export * from './client-error/index.js';
export * from './server-error/index.js';

export {
  GenericHttpError,
};

This is fixed by #50853, which resolves aliases before checking their type/value meaning.

With a top-level doStuff export in ./Foobar, the export type Foobar = import('./Foobar').Foobar and export * as Foobar from './Foobar' pattern produced TS2693 ('Foobar' only refers to a type, but is being used as a value here.) in 4.9.0-dev.20220929. It compiles without that diagnostic in the adjacent 4.9.0-dev.20220930 package and in current native TypeScript.

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Exported type merged with 'export * as namespace...' only exports type meaning. #36792

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Exported type merged with 'export * as namespace...' only exports type meaning. #36792

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jasonkuhrt commented on Sep 1, 2021

nexsodev commented on Oct 12, 2021

RyanCavanaugh commented on Sep 3, 2026

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