I am working on a library using KMP. `KClass.objec...

# multiplatform

[Scott Whitman]

I am working on a library using KMP. KClass.objectInstance doesn't seem to be available on JS or Native, only JVM. Are there any workarounds or libraries that I can use with expext/actual to accomplish something similar to T::class.objectInstance

[Mustafa Ozhan]

Hey not sure what is your scenario but you can do it by using koin , you will need to make the object singleton
example:

single { SomeObject() }

then hold this method in commonMain

fun <T> Koin.getDependency(clazz: KClass<*>): T {
    return get(clazz, null) { parametersOf(clazz.simpleName) } as T
}

this will be used for JS,Android and JVM
in same module add this method in iosMain

fun <T> Koin.getForIOS(objCClass: ObjCClass): T? = getOriginalKotlinClass(objCClass)?.let {
    getDependency(it)
}

you will call this method from Swift code like this,

koin.getForIOS(objCClass: SomeObject.self) as! SomeObject

and from JVM, Android and JS

val someObject: SomeObject by lazy {
    koin.getDependency(SomeObject::class)
}

[Scott Whitman]

I'll have to think if I can make that work for me somehow. Here is what I'm trying to do, the 2nd line in my create function

// common
public expect inline fun <reified T: Any> KClass<T>.objectInstance(): T?
// JVM
//public actual inline fun <reified T: Any> KClass<T>.objectInstance(): T? = T::class.objectInstance
// JS & Native
//public actual inline fun <reified T: Any> KClass<T>.objectInstance(): T? = TODO()

public sealed class KlassInstance<T : Any>(public open val value: Any) {
    public data class Klass<T : Any, R: T>(override val value: KClass<R>) : KlassInstance<T>(value)
    public data class Instance<T : Any, R: T>(override val value: R) : KlassInstance<T>(value)

    public companion object {

        public inline fun <T : Any, reified R: T> create(instance: R? = null): KlassInstance<T> {
            instance?.let { return Instance(it) }
            R::class.objectInstance()?.let{ return Instance(it) }
            return Klass(R::class)
        }
    }
}

[Robert Jaros]

On JS you could probably use:
kClass.js.createInstance()

[Scott Whitman]

Thanks for the tip, I'll try it the next time I'm in front of my computer.

[Scott Whitman]

`createInstance()`is not available on my KClass.js? Is there a dependency I can add to get it?

[Robert Jaros]

I'm sorry, I haven't noticed the createInstance function is in fact my own function 🙂 But feel free to use it:

fun <T> Any?.createInstance(vararg args: dynamic): T {
    val jsClassConstructor = this
    val argsArray = (listOf<dynamic>(null) + args).toTypedArray()
    return js("new (Function.prototype.bind.apply(jsClassConstructor, argsArray))").unsafeCast<T>()
}

[Robert Jaros]

you can make it JsClass<T> extension for your need