Add goal type to JSON response

lib/plausible/goal/schema.ex

@@ -1,8 +1,22 @@
+defimpl Jason.Encoder, for: Plausible.Goal do
+  def encode(value, opts) do
+    goal_type =
+      cond do
+        value.event_name -> :event
+        value.page_path -> :page
+      end
+
+    value
+    |> Map.put(:goal_type, goal_type)
+    |> Map.take([:id, :domain, :goal_type, :event_name, :page_path])
+    |> Jason.Encode.map(opts)
+  end
+end
+
 defmodule Plausible.Goal do
   use Ecto.Schema
   import Ecto.Changeset
 
-  @derive {Jason.Encoder, only: [:id, :domain, :event_name, :page_path]}
   schema "goals" do
     field :domain, :string
     field :event_name, :string

test/plausible_web/controllers/api/external_sites_controller_test.exs

@@ -204,6 +204,7 @@ defmodule PlausibleWeb.Api.ExternalSitesControllerTest do
         })
 
       res = json_response(conn, 200)
+      assert res["goal_type"] == "event"
       assert res["event_name"] == "Signup"
     end
 
@@ -216,6 +217,7 @@ defmodule PlausibleWeb.Api.ExternalSitesControllerTest do
         })
 
       res = json_response(conn, 200)
+      assert res["goal_type"] == "page"
       assert res["page_path"] == "/signup"
     end