Hey guys, does anyone know how to check in Kotlin ...

# javascript

[Joffrey]

Hey guys, does anyone know how to check in Kotlin whether I'm running in NodeJS or in a browser? I tried to test the presence of window but it's always non-null in Kotlin, it just fails at runtime on NodeJS.

[Derek Ellis]

Could you unsafeCast it to something nullable, or wrap it in a try/catch?

[Joffrey]

Being a JS ReferenceError I didn't even think of catching it to be honest... but catch(Throwable) does work. Good point. I was hoping for something more built-in though, as part of the Kotlin JS stdlib

[hfhbd]

These checks are used by Ktor:

public actual val IS_BROWSER: Boolean = js(
        "typeof window !== 'undefined' && typeof window.document !== 'undefined'"
    ) as Boolean

    public actual val IS_NODE: Boolean = js(
        "typeof process !== 'undefined' && process.versions != null && process.versions.node != null"
    ) as Boolean

[Joffrey]

Thanks, this looks better than catching a ReferenceError to me 🙂 but still it would be great if that was in the stdlib

[hfhbd]

I would rather see https://youtrack.jetbrains.com/issue/KT-47038 than this hack :D

[Joffrey]

+1000 to that of course