Support named module wildcard re-export when generating typescript types

[rmja]

↪️ Pull Request

This is a proposal for resolving #5911.

It allows to specify the following in an index.ts file:

export * as SomeExportName from "./some-other-file";

It does not support 1) the case:

import * as SomeExportName from "./some-other-file";
export { SomeExportName };

and, it does not supported 2) nested exports.

If someone can update the test cases for the two unsupported cases so that I can see the expected result, then let me know.

💻 Examples

🚨 Test instructions

✔️ PR Todo

• Added/updated unit tests for this change
• Filled out test instructions (In case there aren't any unit tests)
• Included links to related issues/PRs

[rmja]

Can someone shed some light on why checks on some of the platforms fail?

[mischnic]

You can ignore those. The tests are flakey, as long as one of the integration test jobs passes, you're fine.

[devongovett]

Adding export {hello} from './module1' here results in the types being duplicated, both outside and inside the module block. For strings it's not too bad, but for more complex types might be weird. Maybe we should still hoist the declarations out of the module as before, but create a module like this instead to export them?

export const hello = "world";
export declare module Module1 {
  export {hello};
}

[rmja]

That is a good idea. That could probably also include support for the not supported 1) above.
The problem is then that we very likely gets naming conflicts between the hoisted definitions and the exports. Should we generate some random part in the name to avoid these conflicts?

[devongovett]

I think the hoisting we already do should handle renaming in the top level scope. So you might need something like export {hello1 as hello} within the nested module in that case.

[rmja]

@devongovett could I ask you to roughly commit to this PR the (failing) tests that describes the intended behavior, then I will try and do the implementation.

[ivanbanov]

hey, any timeline for getting this out of the door?