fix(helpers): handle nil case in serialize resource

CHANGELOG.md

@@ -2,6 +2,10 @@
 All notable changes to this project will be documented in this file.
 This project adheres to [Semantic Versioning](http://semver.org/).
 
+### Unreleased
+
+* Fix: add `nil` handling in the `serialize_resource` view helper.
+
 ### v2.1.0
 
 * Swagger has been deleted from the Exposed Api version.

app/helpers/power_api/application_helper.rb

@@ -4,8 +4,7 @@ module ApplicationHelper
 
     def serialize_resource(resource, options = {})
       load_default_serializer_options(options)
-      serializable = ActiveModelSerializers::SerializableResource.new(resource, options)
-      serialized_data = serializable.serializable_hash
+      serialized_data = serialize_data(resource, options)
       render_serialized_data(serialized_data, options)
     rescue NoMethodError => e
       if e.message.include?("undefined method `serializable_hash'")
@@ -19,12 +18,19 @@ def serialize_resource(resource, options = {})
 
     private
 
+    def serialize_data(resource, options)
+      return {} if resource.nil?
+
+      serializable = ActiveModelSerializers::SerializableResource.new(resource, options)
+      serializable.serializable_hash
+    end
+
     def render_serialized_data(serialized_data, options)
       output_format = options.delete(:output_format)
-      serialized_data = serialized_data[:root] if options[:root] == :root
+      serialized_data = serialized_data.fetch(:root, serialized_data)
       return serialized_data if output_format == :hash
 
-      serialized_data.to_json
+      serialized_data.presence.to_json
     end
 
     def load_default_serializer_options(options)

spec/dummy/spec/helpers/power_api/application_helper_spec.rb

@@ -97,6 +97,13 @@ def data
       it { expect(data).to eq(expected_serialized_data) }
     end
 
+    context "with nil resource" do
+      let(:resource) { nil }
+      let(:expected_serialized_data) { "null" }
+
+      it { expect(data).to eq(expected_serialized_data) }
+    end
+
     context "with invalid resource" do
       let(:resource) do
         { invalid: "resource" }
@@ -130,6 +137,13 @@ def data
 
         it { expect(data).to eq(expected_serialized_data) }
       end
+
+      context "with nil resource" do
+        let(:resource) { nil }
+        let(:expected_serialized_data) { {} }
+
+        it { expect(data).to eq(expected_serialized_data) }
+      end
     end
 
     context "with invalid output option" do