extend the list of extensions for module file names in node_modules f…

[vladima]

…older

[mhegazy]

//cc: @sheetalkamat

[mhegazy]

👍

[weswigham]

Errrr, wasn't the reason we had this restriction in the first place because we thought people generally wouldn't want to be inadvertently emitting the TS files we found in their node_modules directory? I understand that in the example in #5225 he wanted, explicitly, to effectively just use his ts files directly for type information, but as it stands right now, if we find a library with both an index.ts and an index.d.ts, we'll find the script file first and (try to) reemit the library on compilation (rather than use any potential existing definitions).

[s-panferov]

@vladima @mhegazy thanks for the fast reaction, this is awesome! The solution is great, but, as @weswigham said, we may want to change the order of extensions here to use a .d.ts first if it is available and than fallback to .ts and .tsx, because it is backwards compatible with previous behaviour.

[mhegazy]

@vladima has a validation tool, that package authors should run. @vladima can you share your tool?

[basarat]

@s-panferov just for your info, a .ts file linked from typings will error out till #5278 is resolved 🌹