Add from to use_helpers to add macro like syntax (#2034)

* add: helpers macro

* refactor helpers macro

* refactor helpers macro

* add: kwargs tests

* add: documentation

* add: changelog entry

* add: block test and use_helper singular method

* fix: ruby2_keywords warnings

* add: singular documentation

* fix: linting

* fix: linting

* fix: lint

* refactor: code

* fix rails main tests

* fix: linting

* fix linting

* fix: linting

* Apply suggestions from code review

---------

Co-authored-by: Joel Hawksley <joel@hawksley.org>
Co-authored-by: Joel Hawksley <joelhawksley@github.com>

docs/CHANGELOG.md

@@ -22,6 +22,10 @@ nav_order: 5
 
     *Reegan Viljoen*
 
+* Add `from:` option to `use_helpers` to allow for more flexible helper inclusion from modules.
+
+    *Reegan Viljoen*
+
 * Fixed ruby head matcher issue.
 
     *Reegan Viljoen*

docs/adrs/0003-polymorphic-slot-definitions.md

@@ -52,7 +52,6 @@ Here's how the `Item` sub-component of the list example above would be implement
 
 ```ruby
 class Item < ViewComponent::Base
-
   renders_one :leading_visual, types: {
     icon: IconComponent, avatar: AvatarComponent
   }

docs/guide/helpers.md

@@ -59,16 +59,40 @@ By default, ViewComponents don't have access to helper methods defined externall
 
 ```ruby
 class UseHelpersComponent < ViewComponent::Base
-  use_helpers :icon
+  use_helpers :icon, :icon?
 
   erb_template <<-ERB
     <div class="icon">
-      <%= icon :user %>
+      <%= icon? ? icon(:user) : icon(:guest) %>
     </div>
   ERB
 end
 ```
 
+Use the `from:` keyword to include individual methods defined in helper modules not available in the component:
+
+```ruby
+class UserComponent < ViewComponent::Base
+  use_helpers :icon, :icon?, from: IconHelper
+
+  def profile_icon
+    icon? ? icon(:user) : icon(:guest)
+  end
+end
+```
+
+The singular version `use_helper` is also available:
+
+```ruby
+class UserComponent < ViewComponent::Base
+  use_helper :icon, from: IconHelper
+
+  def profile_icon
+    icon :user
+  end
+end
+```
+
 ## Nested URL helpers
 
 Rails nested URL helpers implicitly depend on the current `request` in certain cases. Since ViewComponent is built to enable reusing components in different contexts, nested URL helpers should be passed their options explicitly:

lib/view_component/instrumentation.rb

@@ -16,7 +16,7 @@ def render_in(view_context, &block)
           identifier: self.class.identifier
         }
       ) do
-        super(view_context, &block)
+        super
       end
     end
 

lib/view_component/use_helpers.rb

@@ -4,17 +4,27 @@ module ViewComponent::UseHelpers
   extend ActiveSupport::Concern
 
   class_methods do
-    def use_helpers(*args)
-      args.each do |helper_method|
-        class_eval(<<-RUBY, __FILE__, __LINE__ + 1)
-          def #{helper_method}(*args, &block)
-            raise HelpersCalledBeforeRenderError if view_context.nil?
-            __vc_original_view_context.#{helper_method}(*args, &block)
-          end
-        RUBY
+    def use_helpers(*args, from: nil)
+      args.each { |helper_method| use_helper(helper_method, from: from) }
+    end
+
+    def use_helper(helper_method, from: nil)
+      class_eval(<<-RUBY, __FILE__, __LINE__ + 1)
+        def #{helper_method}(*args, &block)
+          raise HelpersCalledBeforeRenderError if view_context.nil?
+
+          #{define_helper(helper_method: helper_method, source: from)}
+        end
+      RUBY
+      ruby2_keywords(helper_method) if respond_to?(:ruby2_keywords, true)
+    end
+
+    private
+
+    def define_helper(helper_method:, source:)
+      return "__vc_original_view_context.#{helper_method}(*args, &block)" unless source.present?
 
-        ruby2_keywords(helper_method) if respond_to?(:ruby2_keywords, true)
-      end
+      "#{source}.instance_method(:#{helper_method}).bind(self).call(*args, &block)"
     end
   end
 end

test/sandbox/app/components/use_helper_macro_component.html copy.erb

@@ -0,0 +1,15 @@
+<div class='helper__message'>
+  <%= message %>
+</div>
+
+<div class='helper__args-message'>
+  <%= message_with_args('macro helper method') %>
+</div>
+
+<div class='helper__kwargs-message'>
+  <%= message_with_kwargs(name: 'macro kwargs helper method') %>
+</div>
+
+<div class='helper__block-message'>
+  <%= block_content %>
+</div>

test/sandbox/app/components/use_helper_macro_component.rb

@@ -0,0 +1,12 @@
+# frozen_string_literal: true
+
+class UseHelperMacroComponent < ViewComponent::Base
+  use_helper :message, from: MacroHelper
+  use_helper :message_with_args, from: MacroHelper
+  use_helper :message_with_kwargs, from: MacroHelper
+  use_helper :message_with_block, from: MacroHelper
+
+  def block_content
+    message_with_block { "Hello block helper method" }
+  end
+end

test/sandbox/app/components/use_helpers_component.rb

@@ -1,5 +1,5 @@
 # frozen_string_literal: true
 
 class UseHelpersComponent < ViewComponent::Base
-  use_helpers :message
+  use_helper :message
 end

test/sandbox/app/components/use_helpers_macro_component.html.erb

@@ -0,0 +1,15 @@
+<div class='helper__message'>
+  <%= message %>
+</div>
+
+<div class='helper__args-message'>
+  <%= message_with_args('macro helper method') %>
+</div>
+
+<div class='helper__kwargs-message'>
+  <%= message_with_kwargs(name: 'macro kwargs helper method') %>
+</div>
+
+<div class='helper__block-message'>
+  <%= block_content %>
+</div>

test/sandbox/app/components/use_helpers_macro_component.rb

@@ -0,0 +1,9 @@
+# frozen_string_literal: true
+
+class UseHelpersMacroComponent < ViewComponent::Base
+  use_helpers :message, :message_with_args, :message_with_kwargs, :message_with_block, from: MacroHelper
+
+  def block_content
+    message_with_block { "Hello block helper method" }
+  end
+end

test/sandbox/app/helpers/macro_helper.rb

@@ -0,0 +1,19 @@
+# frozen_string_literal: true
+
+module MacroHelper
+  def message
+    "Hello helper method"
+  end
+
+  def message_with_args(name)
+    "Hello #{name}"
+  end
+
+  def message_with_kwargs(name:)
+    "Hello #{name}"
+  end
+
+  def message_with_block
+    yield
+  end
+end

test/sandbox/test/rendering_test.rb

@@ -563,7 +563,8 @@ def test_backtrace_returns_correct_file_and_line_number
         render_inline(ExceptionInTemplateComponent.new)
       end
 
-    assert_match %r{app/components/exception_in_template_component\.html\.erb:2}, error.backtrace.first
+    component_error_index = (Rails::VERSION::STRING < "8.0") ? 0 : 1
+    assert_match %r{app/components/exception_in_template_component\.html\.erb:2}, error.backtrace[component_error_index]
   end
 
   def test_render_collection
@@ -1121,4 +1122,52 @@ def test_inline_component_renders_without_trailing_whitespace
 
     refute @rendered_content =~ /\s+\z/, "Rendered component contains trailing whitespace"
   end
+
+  def test_use_helpers_macros
+    render_inline(UseHelpersMacroComponent.new)
+
+    assert_selector ".helper__message", text: "Hello helper method"
+  end
+
+  def test_use_helpers_macros_with_args
+    render_inline(UseHelpersMacroComponent.new)
+
+    assert_selector ".helper__args-message", text: "Hello macro helper method"
+  end
+
+  def test_use_helpers_macros_with_kwargs
+    render_inline(UseHelpersMacroComponent.new)
+
+    assert_selector ".helper__kwargs-message", text: "Hello macro kwargs helper method"
+  end
+
+  def test_use_helpers_with_block
+    render_inline(UseHelpersMacroComponent.new)
+
+    assert_selector ".helper__block-message", text: "Hello block helper method"
+  end
+
+  def test_use_helper_macros
+    render_inline(UseHelperMacroComponent.new)
+
+    assert_selector ".helper__message", text: "Hello helper method"
+  end
+
+  def test_use_helper_macros_with_args
+    render_inline(UseHelperMacroComponent.new)
+
+    assert_selector ".helper__args-message", text: "Hello macro helper method"
+  end
+
+  def test_use_helper_macros_with_kwargs
+    render_inline(UseHelperMacroComponent.new)
+
+    assert_selector ".helper__kwargs-message", text: "Hello macro kwargs helper method"
+  end
+
+  def test_use_helper_macros_with_block
+    render_inline(UseHelperMacroComponent.new)
+
+    assert_selector ".helper__block-message", text: "Hello block helper method"
+  end
 end