Conventions for setting up a GraphQL Server on Rails - Create a comment

create_comment.rb

# app/graphql/mutations/create_comment.rb
module Mutations
  class CreateComment < GraphQL::Schema::Mutation
    argument :post_id, ID, required: true
    argument :comment, String, required: true

    description "Create a comment on a post"

    field :id, ID, null: true
    field :errors, [String], null: false

    def resolve(params)
      # Step 1: Create a mutator.
      mutator = CreateCommentMutator.new(context, params)

      # Step 2: Check if the request is valid?
      if mutator.valid?
        # Step 3.1: A successful response.
        { id: mutator.create_comment.id, errors: [] }
      else
        # Step 3.2: A 'handled' failure.
        { id: nil, errors: mutator.errors.full_messages }
      end
    end
  end
end

# app/graphql/types/mutation_type.rb
module Types
  class MutationType < Types::BaseObject
    field :create_comment, mutation: Mutations::CreateComment, null: false
  end
end