GraphQLのfragmentを使ってみる

$ bundle exec ruby --version
ruby 2.7.5p203 (2021-11-24 revision f69aeb8314) [x86_64-darwin19]

$ bundle exec rails --version
Rails 6.0.4.6

$ bundle info graphql
  * graphql (2.0.13)
	Summary: A GraphQL language and runtime for Ruby
	Homepage: https://github.com/rmosolgo/graphql-ruby
	Path: /Users/xxxxx/.rbenv/versions/2.7.5/lib/ruby/gems/2.7.0/gems/graphql-2.0.13

$ rails db
sqlite> .schema posts
CREATE TABLE IF NOT EXISTS "posts" ("id" integer PRIMARY KEY AUTOINCREMENT NOT NULL, "title" varchar, "description" text, "created_at" datetime(6) NOT NULL, "updated_at" datetime(6) NOT NULL);

# frozen_string_literal: true

module Types
  class PostType < Types::BaseObject
    field :id, ID, null: false
    field :title, String
    field :description, String
    field :created_at, GraphQL::Types::ISO8601DateTime, null: false
    field :updated_at, GraphQL::Types::ISO8601DateTime, null: false
  end
end

module Types
  class QueryType < Types::BaseObject
    field :posts, [Types::PostType], null: false
    def posts
      Post.all.limit(3)
    end
  end
end

fragment Contents on Post {
  title
  description
}

query {
  posts {
    ...Contents
  }
}

{
  "data": {
    "posts": [
      {
        "title": "title_0",
        "description": "desc_0"
      },
      {
        "title": "title_1",
        "description": "desc_1"
      },
      {
        "title": "title_2",
        "description": "desc_2"
      }
    ]
  }
}