register_helper: accept multiple helpers as keyword parameters (#6)

Author: gi

lib/handlebars/engine.rb

@@ -68,9 +68,12 @@ def template(*args)
     # @yieldparam arguments [Object] the arguments (optional)
     # @yieldparam options [Hash] the options hash (optional)
     # @see https://handlebarsjs.com/api-reference/runtime.html#handlebars-registerhelper-name-helper
-    def register_helper(name, &block)
-      attach(name, &block)
-      call(:registerHelper, [name.to_s, name.to_sym], eval: true)
+    def register_helper(name = nil, **helpers, &block)
+      helpers[name] = block if name
+      helpers.each do |n, f|
+        attach(n, &f)
+        call(:registerHelper, [n.to_s, n.to_sym], eval: true)
+      end
     end
 
     # Unregisters a previously registered helper.

spec/handlebars/engine_spec.rb

@@ -146,7 +146,7 @@
 
   describe "#register_helper" do
     let(:name) { :helper }
-    let(:function) { ->(ctx, *args, opts) {} }
+    let(:function) { ->(_ctx, *_args, _opts) { rendered } }
     let(:template) { "{{#{name} name name=name}}" }
 
     before do
@@ -158,7 +158,27 @@
       expect(engine).to respond_to(:register_helper)
     end
 
-    describe "rendering" do
+    context "with positional parameters" do
+      before do
+        engine.register_helper(name, &function)
+      end
+
+      describe "rendering" do
+        include_examples "rendering"
+      end
+    end
+
+    context "with keyword parameters" do
+      before do
+        engine.register_helper(name => function)
+      end
+
+      describe "rendering" do
+        include_examples "rendering"
+      end
+    end
+
+    describe "parameters" do
       describe "the first parameter" do
         it "is the context" do
           render_context.transform_keys!(&:to_s)