Class: GraphQL::Schema::PossibleTypes

Inherits:
Object
  • Object
show all
Defined in:
lib/graphql/schema/possible_types.rb

Overview

Find the members of a union or interface within a given schema.

(Although its members never change, unions are handled this way to simplify execution code.)

Internally, the calculation is cached. It's assumed that schema members don't change after creating the schema!

Examples:

Get an interface's possible types

possible_types = GraphQL::Schema::PossibleTypes(MySchema)
possible_types.possible_types(MyInterface)
# => [MyObjectType, MyOtherObjectType]

Instance Method Summary collapse

Constructor Details

#initialize(schema) ⇒ PossibleTypes

Returns a new instance of PossibleTypes.


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# File 'lib/graphql/schema/possible_types.rb', line 15

def initialize(schema)
  @object_types = schema.types.values.select { |type| type.kind.object? }
  @interface_implementers = Hash.new do |h1, ctx|
    h1[ctx] = Hash.new do |h2, int_type|
      h2[int_type] = @object_types.select { |type| type.interfaces(ctx).include?(int_type) }.sort_by(&:name)
    end
  end
end

Instance Method Details

#interface_implementers(ctx, type_defn) ⇒ Object


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# File 'lib/graphql/schema/possible_types.rb', line 39

def interface_implementers(ctx, type_defn)
  @interface_implementers[ctx][type_defn]
end

#possible_types(type_defn, ctx) ⇒ Object


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# File 'lib/graphql/schema/possible_types.rb', line 24

def possible_types(type_defn, ctx)
  case type_defn
  when Module
    possible_types(type_defn.graphql_definition, ctx)
  when GraphQL::UnionType
    type_defn.possible_types(ctx)
  when GraphQL::InterfaceType
    interface_implementers(ctx, type_defn)
  when GraphQL::BaseType
    [type_defn]
  else
    raise "Unexpected possible_types object: #{type_defn.inspect}"
  end
end