Hey folks, Do you know where I can find an example...

# javascript

[julien lengrand-lambert]

Hey folks, Do you know where I can find an example on how to map Javascript listeners to a Kotlin JS app ? I am specifically looking at https://firebase.google.com/docs/firestore/query-data/listen#web-version-9.

import { doc, onSnapshot } from "firebase/firestore";

const unsub = onSnapshot(doc(db, "cities", "SF"), (doc) => {
    console.log("Current data: ", doc.data());
});

This snippet listens to realtime changes in firestore and triggers the callback function then.

I literally have no clear idea how to bind this with my Kotlin. The main issue I see is that I would need to pass a function as input to the binding, with access to the kotlin side data 🧐

[julien lengrand-lambert]

Well, answering myself, it's easy as one would expect

[julien lengrand-lambert]

on the javascript side, define a function that takes a callback

export function syncMessages(callback){

listen(() => {
    callback()
})

on the kotlin side, call and integrate an anonymous function

@JsModule("@jlengrand/firebase-ports")
@JsNonModule
external object FirebasePorts{
    fun syncMessages(callback: () -> Unit)
}

                                FirebasePorts.syncMessages() { -> println("BOUM") }

[julien lengrand-lambert]

Now, every time listen will be called, so will callback. Haven't tried yet but pretty sure that works with parameters and promises as well

[Derek Ellis]

Couldn't you just call listen() directly from Kotlin and pass it the lambda?

[julien lengrand-lambert]

Hum, that's possible indeed as well

[julien lengrand-lambert]

in my case, I'm trying to now have to use dynamic, nor have to implement too many bindings in Kotlin and listen contains a lot of specific objects

[julien lengrand-lambert]

But in that specific snippet that'd most likely be much better indeed