Is there a way to add a companion object to a clas...

# announcements

[Eivind]

Is there a way to add a companion object to a class from another library. So that i can add extension methods to it. Trying to find a nice way to do SomeDtoClass.generate(10) for a testing solution. Or are there som other nice way?

[Big Chungus]

Nope, original author must leave companion object in the class for you to extend

[ephemient]

https://youtrack.jetbrains.com/issue/KT-11968

[Eivind]

Thank, looks like a popular one. Ill look for another way to get clean code for doing what i want

[sindrenm]

Worth mentioning that if you already do have a companion object on your type, you can add extensions to that one:

class Foo {
    companion object
}

fun Foo.Companion.bar() { println("bar") }

fun main() {
    Foo.bar()
}

But that, of course, requires that you control the type in question, which might not be your case.

[Eivind]

Ended up doing a class to add the extension to. Generator<T> whit a companion object. So i get Ganerator<DTO>(seed).generate(5). It ended up whit about the same readability.

[Nir]

Just out of pure curiosity, why not generate<DTO>(seed, 5)

[Eivind]

Makes it harder to extend. Having the Generator object makes it posible to do fun Generator<Dto2>.generate() and keep the code close to the type.