fixes regression from commit 823148d

Author: adamcreekroad

Gemfile

@@ -1,4 +1,5 @@
 source 'https://rubygems.org'
 gem "opal-jquery", git: "https://github.com/opal/opal-jquery.git", branch: "master"
 gem 'hyperloop-config', git: 'https://github.com/ruby-hyperloop/hyperloop-config.git', branch: 'edge'
+gem 'puma', '~> 3.11.0' # As of adding, version 3.12.0 isn't working so we are locking
 gemspec

lib/react/api.rb

@@ -192,16 +192,22 @@ def self.convert_props(args)
         elsif arg.is_a? Hash
           arg.each do |key, value|
             if ['class', 'className', 'class_name'].include? key
+              next unless value
+
               if value.is_a?(String)
                 value = value.split(' ')
               elsif !value.is_a?(Array)
                 raise "The class param must be a string or array of strings"
               end
-              properties['className'] = (properties['className'] || []) + value
+
+              properties['className'] = [*properties['className'], *value]
             elsif key == 'style'
+              next unless value
+
               if !value.is_a?(Hash)
                 raise "The style param must be a Hash"
               end
+
               properties['style'] = (properties['style'] || {}).merge(value)
             elsif React::HASH_ATTRIBUTES.include?(key) && value.is_a?(Hash)
               properties[key] = (properties[key] || {}).merge(value)

spec/react/param_declaration_spec.rb

@@ -217,6 +217,21 @@ class Tester < Hyperloop::Component
       expect(tp).to have_content('flag: true, a: 1, b: 2, c: 3, d: 4')
     end
 
+    it 'allows passing nil for class and style params' do
+      mount 'Tester' do
+        class Tester < Hyperloop::Component
+          render do
+            DIV(id: 'tp', class: nil, style: nil) { 'Tester' }
+          end
+        end
+      end
+
+      tp = find('#tp')
+
+      expect(tp[:class]).to eq('')
+      expect(tp[:style]).to eq('')
+    end
+
     describe "converts params only once" do
       it "not on every access" do
         mount 'Foo', foo: {bazwoggle: 1} do