Table of Contents
Enum type
Union Type
A union type is a set of object types that may appear in the same spot.
That means the spot only returns one object, in this case, either AudioClilp or VideoClip.
module Types
class AudioClipType < Types::BaseObject
field :id, Int, null: false
field :duration, Int, null: false
end
end
module Types
class MovieClipType < Types::BaseObject
field :id, Int, null: false
field :previewURL, String, null: false
field :resolution, Int, null: false
end
end
module Types
class MediaItemType < Types::BaseUnion
possible_types Types::AudioClipType, Types::MovieClipType
def self.resolve_type(object, context)
if object.is_a?(AudioClip)
Types::AudioClipType
else
Types::MovieClipType
end
end
end
end
module Types
class PostType < Types::BaseObject
description 'Post'
field :id, Int, null: false
field :media_item, Types::MediaItemType, null: true
def media_item
return object.audio_clip if object.audio_clip
object.video_clip
end
end
end- GraphQL - Object Identification Hooks
- Youtube video about graphql Union Type
- Unions and interfaces - Apollo Server - Apollo GraphQL Docs
- GraphQL: Union vs. Interface - Artsy Engineering
Interface
Interfaces are a good choice whenever a set of objects are used interchangeably, and they have several significant fields in common. When they don’t have fields in common, use a Union instead.
interface Customer {
name: String!
outstandingBalance: Int!
}
type Company implements Customer {
employees: [Individual!]!
name: String!
outstandingBalance: Int!
}
type Individual implements Customer {
company: Company
name: String!
outstandingBalance: Int!
}Fragments
A GraphQL fragment is a shared piece of query logic.
fragment NameParts on Person {
firstName
lastName
}
query GetPerson {
people(id: "7") {
...NameParts
avatar(size: LARGE)
}
}Connection_type
Connection will help you paginate through the list of comments connected to the post with 4 default arguments (first, last, after and before) in the query, whereas field here would return a basic list of CommentType.
Relays
A Facebook page contains several elements and React components, which have different data requirements. GraphQL allows to list all the data we need to generate a page in a single top level query. So we save network from sending multiple requests by querying the data we need in a single round-trip.