Objects and Interfaces

GraphQL Objects and Interfaces represent a list of named fields, each of which yield a value of a specific type. KGraphQL inspects defined operations to create type system, but schema creator is able to explicitly declare and customize types. Besides, only member properties are inspected.

type { }

type method is entry point to Type DSL. See Extension Properties, Kotlin Properties, Union Properties.

Example

data class Person(val name: String, val age: Int)

KGraphQL.schema {
    type<Person>{
        description = "Human"
    }
}

KProperty1<T, R>.ignore

extension function ignore() makes KGraphQL ignore its receiver property.

Example

data class Person(val name: String, val age: Int)

KGraphQL.schema {
    type<Person>{
        Person::age.ignore()
    }
}

transformation(KProperty1<T, R>) {}

transformation method allows schema creator to attach data transformation on any kotlin property of type. Like operations, transformation has property resolver which is used to declare data transformation.

Example

data class Person(val name: String, val age: Int)

KGraphQL.schema {
    type<Person>{
       transformation(Person::age) {
            //inMonths is nullable, so client can fetch age property without passing any value to this argument
            //if(null == true) evaluates to false, if(null) is invalid kotlin code
            age: Int , inMonths : Boolean? -> if(inMonths == true) age * 12 else age
        }
   }
}