:wave: Heya! I'm working with Google PubSub and have the following external declarations ```@file:Js...

# javascript

[georgi]

👋 Heya! I'm working with Google PubSub and have the following external declarations

@file:JsModule("@google-cloud/pubsub")
@file:JsNonModule

@JsName("PubSub")
external class GoogleCloudPubSub {
    fun topic(name: String): GoogleCloudPubSubTopic
}

external class GoogleCloudPubSubTopic {
    fun exists(): Promise<Boolean>
}

Elsewhere I'm using this as

launch {
    val topic = GoogleCloudPubSub().topic("blah-blah")
    val result = topic.exists().await()
    println(result)
    if (result) { println("Exists") } else { println("Doesn't exist") }
}

The first print correctly shows true | false for the result of exists(). However, the if statement never runs even if result is true - if I do something like this val result = topic.exists().await().toString()._toBoolean_() it works fine.

Any ideas as to why it's happening? Thanks in advance 🙏

[georgi]

I think I've found the problem. My external definition seems to be wrong. PubSub defines exists as

exists(): Promise<ExistsResponse>;
export type ExistsResponse = [boolean];

and in my case I interfaced it as fun exists(): Promise<Boolean> which I think was triggering the truthy Promise behaviour of always having a "true" response.

I changed my code to

fun exists(): Promise<Array<Boolean>>
...
if (topic.exists().await().first()) {
    ...
}

and now the Promise resolves correctly.