Merge pull request #27 from bbalser/merge_function_default

Change for merge with a function to call the function with a value of…

lib/brook/view_state.ex

@@ -122,7 +122,7 @@ defmodule Brook.ViewState do
     assert_environment()
 
     case get(instance(), collection, key) do
-      {:ok, nil} -> default
+      {:ok, nil} -> default || function.(nil)
       {:ok, old_value} -> function.(old_value)
       {:error, reason} -> raise RuntimeError, message: inspect(reason)
     end

test/unit/view_state_test.exs

@@ -41,6 +41,10 @@ defmodule Brook.ViewStateTest do
       merge(:data, data["id"], data)
       merge(:data, data["id"], %{second_merge: true})
     end
+
+    def handle_event(%Brook.Event{type: "function_merge", data: data}) do
+      merge(:data, data["id"], fn _old -> data end)
+    end
   end
 
   setup do
@@ -119,6 +123,14 @@ defmodule Brook.ViewStateTest do
         assert %{"id" => 18, "name" => "Bill", second_merge: true} == Brook.get!(@instance, :data, 18)
       end
     end
+
+    test "data can be merged with a function and no current value" do
+      send_event("function_merge", %{"id" => 23, "name" => "Nathaniel"})
+
+      assert_async do
+        assert %{"id" => 23, "name" => "Nathaniel"} == Brook.get!(@instance, :data, 23)
+      end
+    end
   end
 
   describe "delete" do