Extending a namespace in `.d.ts` file vs in `.ts` file

[realyze]

Typescript@2.1.6

Using "@types/react": "^0.14.41", and "@types/react-dom": "^0.14.18" (installed via npm).

When I write

declare module 'react' {
    interface HTMLProps<T> {
        onTouchTap?: React.EventHandler<React.TouchEvent<T>>;
    }
}

in a customTypings/react-tap-touch.d.ts file, it seems to cause tsc to report a lot of errors (error TS2604: JSX element type 'Router' does not have any construct or call signatures and similar). Looks like react namespace is overriden rather than extended.

Using the same snippet in a startup.ts file works fine (i.e., extends react and doesn't override it).

What's the difference between extending a namespace from .d.ts vs .ts file? Shouldn't .d.ts be the right place to do this sort of thing?

The issue is summed up by this comment:
zilverline/react-tap-event-plugin#58 (comment)

[blakeembrey]

They should be the same. However, they are different depending on if you have import or export at the top-level. With import and export, you're writing a module augmentation (because the file is in "module mode"). Without them, you're writing a module declaration (because the file is in "global mode").

Edit: Your problem would be resolved if you do import * as react from 'react' before trying to augment it.

[realyze]

@blakeembrey Thanks a lot!