Ensure formatted json encoding for nil (#94)

lib/live_view_native/stylesheet/encoder.ex

@@ -7,6 +7,9 @@ defmodule LiveViewNative.Stylesheet.Encoder do
   def format({name, value}, encoder, state) when is_atom(name),
     do: :json.format_value(%{{name, value}}, encoder, state)
 
+  def format(nil, _encoder, _state),
+    do: ~c(null)
+
   def format(atom, encoder, state) when is_atom(atom) do
     cond do
       Code.ensure_loaded?(atom) ->

test/live_view_native/stylesheet/encoder_test.exs

@@ -1,7 +1,15 @@
 defmodule LiveViewNative.Stylesheet.EncoderTest do
   use ExUnit.Case
 
-  test "nil" do
-    assert :json.encode(nil, &LiveViewNative.Stylesheet.Encoder.encode/2) == ~c(null)
+  describe "encoder" do
+    test "nil" do
+      assert :json.encode(nil, &LiveViewNative.Stylesheet.Encoder.encode/2) == ~c(null)
+    end
+  end
+
+  describe "formatter" do
+    test "nil" do
+      assert :json.format(nil, &LiveViewNative.Stylesheet.Encoder.format/3) == [~c(null), ?\n]
+    end
   end
 end