Hello, I am trying to implement some basic pagination and it seems like I should be using generics, ...

# graphql-kotlin

[Dusan Hornik]

Hello, I am trying to implement some basic pagination and it seems like I should be using generics, but that doesn’t generate graphql schema:

com.expediagroup.graphql.exceptions.TypeNotSupportedException: Cannot convert T since it is not a valid GraphQL type or outside the supported packages

Code:

class MyQuery: Query {}
    suspend fun students(pageNumber:Int): Page<Student> {
      return getStudents(pageNumber)
    } 
}
data class Page<T>(val items: List<T>, pageNumber: Int)
data class Student(val name: String)

Is there a recommended way to design this?

[Dariusz Kuc]

Hello 👋
TLDR generics are not supported by GraphQL spec so we don't support it either (https://github.com/ExpediaGroup/graphql-kotlin/issues/292)

[Dariusz Kuc]

While it is not ideal, the workaround is to create specific Page flavors (i.e. StudentPage instead of generic Page<T>)

[Dusan Hornik]

Yeah, that’s what I thought so. Thank you Dariusz.