Is there a way to disallow extensions on a class? Details in :thread:

# codereview

[Seth Madison]

Is there a way to disallow extensions on a class?

Details in 🧵

[Seth Madison]

The most performant way that I’ve found to parse JSON using KotlinJS is to use native JSON.parse to produce a dynamic, and then unsafeCast it to an exported class. This works great, and allows for code sharing across targets (contrasted with external interface). This looks like:

The problem is that you end up with an incomplete instance of the class, and so if there are extension functions defined on the class, they’ll crash at runtime.

I would like to define a JsExport class that cannot receive extensions so that users of the class don’t accidentally write code that will crash at runtime!

[Jan]

Not exactly what you might want, but you could wrap into value class and avoid auto complete for default extensions 😅