Hi team is it possible to use Kotlin JS without `kotlin stdl

Question

Hi team is it possible to use Kotlin JS without `kotlin stdlib` I have a KMM project for JVM iOS and JS And I need to reduce the size of the JS package

turansky · Answer

Do you mean concrete packages classes

goku · Answer

Yes stdlib adds a lot of overhead and increases the package size The clients are avoiding to adopt it I understand stdlib provides all the convenience of what makes Kotlin but this is a small JSON serializer project and I m wondering if I can do it in a way that is minimal

turansky · Answer

Do you use IR compiler

goku · Answer

Yes

Adam S · Answer

if you just want to share TypeScript interfaces so clients can decode JSON then you could consider using Kotlinx Serialization and <https adamko dev github io kotlinx serialization typescript generator |kxs ts gen> to generate TypeScript interfaces from Kotlin code

goku · Answer

This would defeat the purpose of the library I provide interfaces that takes a json string performs some operation on them and then returns back a json string If there was a way to optimize what is included stdlib that would be super beneficial There is a lot of functionality that gets exported but not used

Vampire · Answer

If you are using IR compiler and building for production target afaik dead code elimination should be built into the compiler and throw out the unused stuff doesn t it

Adam S · Answer

another alternative you could try excluding the stdlib completely and copy+paste only what you need from the stdlib <https kotlinlang org docs gradle configure project html dependency on the standard library> ```kotlin stdlib default dependency=false```

goku · Answer

You are right upon further analyzing by removing adding pieces I can see that stdlib only exports what s being used I think the only way to further optimize is to replace kotlinx Json with JSON parser and avoid using certain types like Map

jessewilson · Answer

I ve been down this road and it s possible You ll need to avoid List and Map and RegEx which gets pretty onerous

jessewilson · Answer

You ll probably want to make a Gradle task to scan your generated JS files for uses of RegEx and List and fail your build if you accidentally re introduce them

jessewilson · Answer

Turns out that calls to functions like String split drag in RegEx

jessewilson · Answer

And that brings in List which brings in all the collections and the game is lost

jessewilson · Answer

Also when I did this I ended up creating a custom StringMap and JsArray types that were backed by basic JavaScript objects on JS and proper collections on other platforms

jessewilson · Answer

This really sucked

goku · Answer

Thanks for the insights Jesse I was gonna actually post an update on this I did play around by removing replacing code and reduced it to `227KB` and `40KB` after compressing I removed `kolinx serialization json` and used JSON parser I didn t remove the List Map RegEx but at that point we just decided to rewrite it in Javascript Either way we have two different implementations KMM would be really handy for an internal tool but for a product we ship where the size important it made more sense to rewrite it in JS