I keep running into this issue - ```TypeError: tmp$.iterator is not a function``` while iterating a...

# javascript

[Gurupad Mamadapur [FH]]

I keep running into this issue -

TypeError: tmp$.iterator is not a function

while iterating a nullable list type. (Kotlin/js - 1.3.61). Also, this is an MPP project using coroutines. This error occurs inside a coroutine

Ex -

val marked: List<User> = dto.accounts?.map { User(it) } ?: listOf()

// where accounts is of type List<T>?

[Gurupad Mamadapur [FH]]

Webpack error message -

Could not load content for webpack:///generated/_Collections.kt?f709 : HTTP status code: 404

Maybe this is the main issue.

[Gurupad Mamadapur [FH]]

If I switch to Array<T>? it works fine.

[rnentjes]

Is this data (dto.accounts) by any chance coming from json?

[Gurupad Mamadapur [FH]]

Yep, and it is serialized using JSON.parse

[rnentjes]

When you parse from json the prototype is not set on the javascript objects and methods don't work.

[rnentjes]

When you use kotlinx.serialization you don't have this problem. Or keep the dto's simple and use arrays i.o. lists.

[rnentjes]

Btw, extension functions will still work, so that might help.

[Gurupad Mamadapur [FH]]

Oh okay, thanks. The problem I had with kotlinx.serialization was with generics. I want to serialize SomeCustomClass<T>, but right now it only supports List<T> and some other basic ones.

link - https://kotlinlang.slack.com/archives/C7A1U5PTM/p1578059023023800

[rnentjes]

I responded to the question about serializing generics, which is possible.