hello-world-relay-part-2 - Schema definition (golang)

schema.go

package data

import (
  "github.com/graphql-go/graphql"
  "github.com/graphql-go/relay"
)

var postType *graphql.Object
var queryType *graphql.Object
var Schema graphql.Schema

func init() {
  postType = graphql.NewObject(graphql.ObjectConfig{
    Name: "Post",
    Fields: graphql.Fields{
      // Define `id` field as a Relay GlobalID field.
      // It helps with translating your GraphQL object's id into a global id
      // For eg:
      //  For a `Post` type, with an id of `1`, it's global id will be `UG9zdDox`
      //  which is a base64 encoded version of `Post:1` string
      // We will explore more in the next part of this series.
      "id": relay.GlobalIDField("Post", nil),
      "text": &graphql.Field{
        Type: graphql.String,
      },
    },
  })

  queryType = graphql.NewObject(graphql.ObjectConfig{
    Name: "Query",
    Fields: graphql.Fields{
      "latestPost": &graphql.Field{
        Type: postType,
        Resolve: func(p types.ResolveParams) interface{} {
          return GetLatestPost()
        },
      },
    },
  })

  Schema, _ = graphql.NewSchema(graphql.SchemaConfig{
    Query: queryType,
  })

}

where is the types come from at this line https://gist.github.com/sogko/c763cd9fbc14d197a76e#file-schema-go-L34 ?