Allow generator to use options

lib/hamlit/engine.rb

@@ -18,7 +18,10 @@ module Hamlit
     filter :MultiFlattener
     filter :StaticMerger
     use :Generator do
-      options[:generator].new
+      valid_options = options.to_hash.select do |key, value|
+        options[:generator].options.valid_key?(key)
+      end
+      options[:generator].new(valid_options)
     end
   end
 end

spec/hamlit/engine_spec.rb

@@ -0,0 +1,16 @@
+describe Hamlit::Engine do
+  describe '.new' do
+    subject { described_class.new(options) }
+
+    let(:buffer)  { '_a' }
+    let(:options) do
+      { buffer: buffer, generator: Temple::Generators::ArrayBuffer }
+    end
+
+    it 'allows generator valid options' do
+      expect(subject.call('')).to eq(
+        "#{buffer} = []; ; #{buffer} = #{buffer}.join",
+      )
+    end
+  end
+end