Is it possible to detect somehow which backend (le...

# javascript

[Robert Jaros]

Is it possible to detect somehow which backend (legacy or ir) was used to compile the Kotlin/JS code?

[Big Chungus]

It's specified in gradle metadata so you could parse that

[Svyatoslav Kuzmich [JB]]

In terms of generated JS: If you see stdlib imported with the name “Kotlin” and names are mangled with base64 hash like this println_s8jyv4$ — it is a legacy compiler.

[Svyatoslav Kuzmich [JB]]

In terms of kotlin libraries: IR is published as klib, legacy — jar with JS inside.

[Big Chungus]

https://gitlab.com/martynas.petuska/kamp/-/blob/master/scanner/src/main/kotlin/scanner/processor/GradleModuleProcessor.kt#L17

[Robert Jaros]

In fact I needed to detect how a data class is represented in JS code (legacy - plain fields, ir with @JsExport- defined properties with getters and setters). For know I've created this "hack":

val prototype = js("Object").getPrototypeOf(obj)
    val prototypeProps: Array<String> = js("Object").getOwnPropertyNames(prototype)
    val isLegacy = prototypeProps.filterNot { prototype.propertyIsEnumerable(it) }.toSet() == setOf("constructor")

It seems to work for my use cases 😉

[Robert Jaros]

BTW any chance of resolving https://youtrack.jetbrains.com/issue/KT-41162 ? It's a nightmare when it comes to integration with external JS libraries.

[bashor]

@Robert Jaros we are considering it