Kotlin Native is what you are looking for.

Or maybe j2Objc

One codebase for both platforms is not necessarily what you want though.

Let me rephrase, it might be what you want for a pretty small app : if you have to create an app for a restaurant with orders and menu, a cross platform solution is probably the best use of your time.

For anything bigger, it becomes a harder sell. All these solutions tend to have the same downsides :

- limited access to new platform features. Especially damaging when Apple tells you that you are going to get featured if you do a Watch app but your SDK does not support that yet.

- one design does not scale well to two platforms with different UX and features.

- one more layer of abstraction to manage; making maintainability harder

I think that there is clearly a space for a cross platform business logic framework though. It tends to be the same on both platform with minor differences. It is a pity that only j2objc seems to clearly target this. k2objc/swift would be awesome.

Don’t mix platform and language. Having same language is just 5% of one platform for iOS android and windows. Weex gives also web mobile support btw.

Yes, it's called Kotlin Native: https://github.com/JetBrains/kotlin-native

Kotlin right now is a serious competitor for a full stack, any device language. An alternative may be F# which has Fable for Browser, Xamarin (mobile) and .net core for server. But Kotlin looks more integrated to me.

Coming from a C#/F# background, Kotlin is really a joy to use.

Yeah, if they play it right they can be one-size-fits-all solution. A question is if they would take risks with such approach as their motto is to "implement stuff that is winning", i.e. copying things others did and that worked well (in commercial sense) and avoid experimental stuff that doesn't bring money in.

It's not production ready yet, but Kotlin Native is probably the way to go for iOS support.

https://github.com/JetBrains/kotlin-native

There's an announcement and some example code for building iOS apps with Kotlin/Native here, including reusing some of the code across iOS and Android:

https://blog.jetbrains.com/kotlin/2017/11/kotlinconf-keynote...

I'm waiting for Kotlin-based React Native alternative without any trace of JavaScript (in mobile). Kotlin JVM for Android and server rendering, Kotlin Native for iOS, Kotlin JavaScript for Web. Makes more sense than JavaScript everywhere.