absinthe
absinthe v1.7.0

View Source Absinthe.Type.Union (absinthe v1.7.0)

A unions is an abstract type made up of multiple possible concrete types.

No common fields are declared in a union. Compare to Absinthe.Type.Interface.

Because it's necessary for the union to determine the concrete type of a resolved object, you must either:

  • Provide a :resolve_type function on the union
  • Provide a :is_type_of function on each possible concrete type
union :search_result do
  description "A search result"

  types [:person, :business]
  resolve_type fn
    %Person{}, _ -> :person
    %Business{}, _ -> :business
  end
end

Link to this section Summary

Types

t()
  • :name - The name of the union type. Should be a TitleCased binary. Set automatically.
  • :description - A nice description for introspection.
  • :types - The list of possible types.
  • :resolve_type - A function used to determine the concrete type of a resolved object. See also Absinthe.Type.Object's :is_type_of. Either resolve_type is specified in the union type, or every object type in the union must specify is_type_of

The :resolve_type function will be passed two arguments; the object whose type needs to be identified, and the Absinthe.Execution struct providing the full execution context.

Functions

kind()

Callback implementation for c:Absinthe.Introspection.TypeKind.kind/0.

Link to this section Types

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t()

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Specs

t() :: %Absinthe.Type.Union{
  __private__: Keyword.t(),
  __reference__: Absinthe.Type.Reference.t(),
  definition: module(),
  description: binary(),
  fields: map(),
  identifier: atom(),
  name: binary(),
  resolve_type: term(),
  types: [Absinthe.Type.identifier_t()]
}
  • :name - The name of the union type. Should be a TitleCased binary. Set automatically.
  • :description - A nice description for introspection.
  • :types - The list of possible types.
  • :resolve_type - A function used to determine the concrete type of a resolved object. See also Absinthe.Type.Object's :is_type_of. Either resolve_type is specified in the union type, or every object type in the union must specify is_type_of

The :resolve_type function will be passed two arguments; the object whose type needs to be identified, and the Absinthe.Execution struct providing the full execution context.

The __private__ and :__reference__ keys are for internal use.

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kind()

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Callback implementation for c:Absinthe.Introspection.TypeKind.kind/0.