Adding a count to an absinthe_relay Connection

query.graphql

{
  items(first: 5) {
    count
    edges {
      node {
        name
      }
    }
  }
}

result.json

{
  "data": {
    "items": {
      "edges": [
        {
          "node": {
            "name": "Item #1"
          }
        },
        {
          "node": {
            "name": "Item #2"
          }
        },
        {
          "node": {
            "name": "Item #3"
          }
        },
        {
          "node": {
            "name": "Item #4"
          }
        },
        {
          "node": {
            "name": "Item #5"
          }
        }
      ],
      "count": 1000
    }
  }
}

schema.ex

defmodule ScrogsoApp.Web.Schema do
  use Absinthe.Schema
  use Absinthe.Relay.Schema
  import Ecto.Query

  alias ScrogsonApp.{Example, Repo}

  connection node_type: :item do
    field :count, non_null(:integer)
    edge do
      # Because we're extending the connection type, we need to
      # manually force the edge type to be created with this macro.
    end
  end

  node interface do
    resolve_type fn
      %Example.Item{}, _ ->
        :item
      _, _ ->
        nil
    end
  end

  node object :item do
    field :name, :string
  end

  query do
    connection field :items, node_type: :item do
      resolve fn args, _ ->
        # Simple query w/out filtering, etc
        query = from t in Example.Item
        count = Repo.one!(from item in query, select: count(item.id))
        result =
          Absinthe.Relay.Connection.from_query(query, &Repo.all/1, args)
          |> Map.put(:count, count)
        {:ok, result}
      end
    end
  end

end