I'm getting this error after calling a fun that returns a Promise: `Unhandled Runtime Error TypeErro...

# multiplatform

[Luan Pereira]

I'm getting this error after calling a fun that returns a Promise:
Unhandled Runtime Error TypeError: hidden._get_entries__31877249_iz8n5_k$ is not a function

browser request is responding 200

Any idea?

The fun in js target:

fun initialize (formId: String, hidden: Map<String, String>): Promise<InitializationResult> = GlobalScope.promise{ internalForm.initialize(formId, hidden)}

[Trevor Stone]

Are you calling from js or calling from kotlin? Js doesn't know what a map is

[Luan Pereira]

I'm calling from js (browser)

What would be the ideal way to get around this?

I can't use Map any time? even inside commonMain?

the hidden parameter is dynamic :/

[Trevor Stone]

So if you are calling this function directly from JS (the function is annotated with JSExport), then you can not use a map directly no. If it is inside of commonMain and called from other Kotlin code you can use Maps

[Trevor Stone]

https://kotlinlang.org/docs/js-to-kotlin-interop.html#kotlin-types-in-javascript

[Trevor Stone]

The solution here kind of depends on what you're looking to do as well as if this is part of shared code vs js specific code

[Trevor Stone]

For example if this is just for JS code you could use a Json instead of a Map https://kotlinlang.org/api/latest/jvm/stdlib/kotlin.js/-json/

[Trevor Stone]

but you lose the type safety of the value being a string

[Trevor Stone]

You could also instead have the param be an array of Pair<String,String> and then convert it to a Map internally

[Trevor Stone]

I don't know the context for what hidden is being used for, so that would probably also adjust the solution

[Trevor Stone]

You could also create a public MapBuilder function that returns a Map with whatever syntax you choose, and you could use that returned Map for this param

[Trevor Stone]

but essentially the issues is that JS doesn't know what a Kotlin Map is, and there isn't a direct simple translation

[Luan Pereira]

The parameter will be passed directly to an API call..

We decided to use Json and MutableMap here.

[Luan Pereira]

You clarified some things for me

[Luan Pereira]

Thank you so much

[Trevor Stone]

Happy to help. Kotlin/JS has some of the most unique behavior at the exposed API layer (JSExport, Collection types, etc) compared to Kotlin/JVM and Kotlin/Native, so I ran into a lot of things in the past around trying to make a multiplatform project feel uniform between Mobile and Web