Typescript: Attaching property to exported function creates invalid definition file

[SimenB]

TypeScript Version: 3.3.0-dev.20181229

Search Terms:
default export function property namespace

Code

export default function someFunc() {
    return 'hello!';
}

someFunc.someProp = 'yo';

Expected behavior:
The declaration file should be valid

Actual behavior:

packages/proj-1/build/index.d.ts:2:26 - error TS1005: ';' expected.

2 export default namespace someFunc {
                           ~~~~~~~~

packages/proj-1/build/index.d.ts:2:35 - error TS1005: ';' expected.

2 export default namespace someFunc {

Playground Link: Cannot be reproduced in the playground as the issue is in the d.ts file, not the JS. However, I've setup a repository: https://github.com/SimenB/tsc-b-auch

Related Issues: None found

[SimenB]

Note that the file is generated successfully, it's only when trying to consume it things fall apart

[DanielRosenwasser]

Haven't tried this, but you can probably get around this by writing

function someFunc() {
    return 'hello!';
}

someFunc.someProp = 'yo';

export default someFunc;

[SimenB]

Yeah, that works! Thanks 🙂

[DanielRosenwasser]

Thanks @Kingwl!

[Diokuz]

Have the same issue.
@DanielRosenwasser Is this by design?

yarn tsc --version
Version 3.4.5

[DanielRosenwasser]

This is scheduled for 3.5.0. You can npm install typescript@next and if you're still seeing issues, open up a new issue.