Add to_component_class to active record base

.github/workflows/ruby_on_rails.yml

@@ -22,6 +22,7 @@ jobs:
         ruby-version: ${{ matrix.ruby_version }}
     - name: Build and test with Rake
       run: |
+        sudo apt-get install libsqlite3-dev
         gem install bundler:1.14.0
         bundle update
         bundle install --jobs 4 --retry 3

.gitignore

@@ -47,5 +47,7 @@ build-iPhoneSimulator/
 # .ruby-version
 # .ruby-gemset
 
+/**/*.sqlite3
+
 # unless supporting rvm < 1.11.0 or doing something fancy, ignore this:
 .rvmrc

Gemfile

@@ -6,3 +6,4 @@ gemspec
 rails_version = "#{ENV['RAILS_VERSION'] || '6.0.0'}"
 
 gem "rails", rails_version == "master" ? { github: "rails/rails" } : rails_version
+gem "sqlite3", rails_version >= "6.0.0" ? ">= 1.4.0" : "< 1.4.0"

Gemfile.lock

@@ -146,6 +146,7 @@ GEM
       actionpack (>= 4.0)
       activesupport (>= 4.0)
       sprockets (>= 3.0.0)
+    sqlite3 (1.4.1)
     temple (0.8.1)
     thor (0.20.3)
     thread_safe (0.3.6)
@@ -171,6 +172,7 @@ DEPENDENCIES
   rubocop (= 0.74)
   rubocop-github (~> 0.13.0)
   slim (~> 4.0)
+  sqlite3 (>= 1.4.0)
 
 BUNDLED WITH
    1.17.3

README.md

@@ -163,6 +163,24 @@ Components can be rendered via:
 
 `render(component: TestComponent, locals: { foo: :bar })`
 
+**Rendering components through models**
+
+Passing model instances will cause `render` to look for its respective component class.
+
+The component is instantiated with the rendered model instance.
+
+Example for a `Post` model:
+
+`render(@post)`
+
+```ruby
+class PostComponent < ActionView::Component
+  def initialize(post)
+    @post = post
+  end
+end
+```
+
 The following syntax has been deprecated and will be removed in v2.0.0:
 
 `render(TestComponent.new(foo: :bar))`

lib/action_view/component.rb

@@ -1,5 +1,6 @@
 # frozen_string_literal: true
 
 require "action_view/component/monkey_patch"
+require "action_view/component/active_model_conversion_monkey_patch"
 require "action_view/component/base"
 require "action_view/component/railtie"

lib/action_view/component/active_model_conversion_monkey_patch.rb

@@ -0,0 +1,9 @@
+# frozen_string_literal: true
+
+module ActiveModel
+  module Conversion
+    def to_component_class
+      "#{self.class.name}Component".safe_constantize
+    end
+  end
+end

lib/action_view/component/monkey_patch.rb

@@ -17,6 +17,8 @@ def render(options = {}, args = {}, &block)
         options.new(args).render_in(self, &block)
       elsif options.is_a?(Hash) && options.has_key?(:component)
         options[:component].new(options[:locals]).render_in(self, &block)
+      elsif options.respond_to?(:to_component_class) && !options.to_component_class.nil?
+        options.to_component_class.new(options).render_in(self, &block)
       else
         super
       end

test/action_view/component_test.rb

@@ -251,6 +251,13 @@ def test_renders_component_with_rb_in_its_name
     assert_equal "Editorb!\n", render_inline(EditorbComponent).text
   end
 
+  def test_to_component_class
+    post = Post.new(title: "Awesome post")
+
+    assert_equal PostComponent, post.to_component_class
+    assert_equal "<span>The Awesome post component!</span>", render_inline(post).first.to_html
+  end
+
   private
 
   def modify_file(file, content)

test/app/components/post_component.html.erb

@@ -0,0 +1 @@
+<span>The <%= @post.title %> component!</span>

test/app/components/post_component.rb

@@ -0,0 +1,7 @@
+# frozen_string_literal: true
+
+class PostComponent < ActionView::Component::Base
+  def initialize(post)
+    @post = post
+  end
+end

test/app/models/application_record.rb

@@ -0,0 +1,5 @@
+# frozen_string_literal: true
+
+class ApplicationRecord < ActiveRecord::Base
+  self.abstract_class = true
+end

test/app/models/post.rb

@@ -0,0 +1,4 @@
+# frozen_string_literal: true
+
+class Post < ApplicationRecord
+end

test/config/application.rb

@@ -2,6 +2,7 @@
 
 require File.expand_path("../boot", __FILE__)
 
+require "active_record/railtie"
 require "active_model/railtie"
 require "action_controller/railtie"
 require "action_view/railtie"

test/config/database.yml

@@ -0,0 +1,8 @@
+default: &default
+  adapter: sqlite3
+  pool: <%= ENV.fetch("RAILS_MAX_THREADS") { 5 } %>
+  timeout: 5000
+
+test:
+  <<: *default
+  database: db/test.sqlite3

test/test_helper.rb

@@ -16,3 +16,11 @@
 def trim_result(html)
   html.delete(" \t\r\n")
 end
+
+ActiveRecord::Base.establish_connection(adapter: "sqlite3", database: ":memory:")
+
+ActiveRecord::Schema.define do
+  create_table :posts, force: true do |t|
+    t.string :title
+  end
+end