# Opal Rails [](http://travis-ci.org/elia/opal-rails) [](https://codeclimate.com/github/elia/opal-rails) _Rails (3.2+, 4.0) bindings for [Opal Ruby](http://opalrb.org) engine._ ## Installation In your `Gemfile` ``` ruby gem 'opal-rails' ``` or when you build your new Rails app: ```bash rails new <app-name> --javascript=opal ``` ## Usage ### Asset Pipeline ```js // app/assets/application.js.rb //= require opal //= require opal_ujs //= require turbolinks //= require_tree . ``` Opal requires are forwarded to the Asset Pipeline at compile time (similarly to what happens for RubyMotion). You can use either the `.rb` or `.opal` extension: ```ruby # app/assets/javascripts/greeter.js.rb puts "G'day world!" # check the console! # Dom manipulation require 'opal-jquery' Element.find('body > header').html = '<h1>Hi there!</h1>' ``` ### As a template You can use it for your views too, it even inherits instance and local variables from actions: ```ruby # app/controllers/posts_controller.rb def create @post = Post.create!(params[:post]) render type: :js, locals: {comments_html: render_to_string(@post.comments)} end ``` Each assign is filtered through JSON so it's reduced to basic types: ```ruby # app/views/posts/cerate.js.opal post = Element.find('.post') post.find('.title').html = @post[:title] post.find('.body').html = @post[:body] post.find('.comments').html = comments_html ``` ### As an Haml filter (optional) Of course you need to require `haml-rails` separately since its presence is not assumed ```haml -# app/views/posts/show.html.haml %article.post %h1.title= post.title .body= post.body %a#show-comments Display Comments! .comments(style="display:none;") - post.comments.each do |comment| .comment= comment.body :opal Document.ready? do Element.find('#show-comments').on :click do |click| click.prevent_default click.current_target.hide Element.find('.comments').effect(:fade_in) end end ``` ### Spec! Add specs into `app/assets/javascripts/specs`: and then a spec folder with you specs! ```ruby # app/assets/javascripts/spec/example_spec.js.rb describe 'a spec' do it 'has successful examples' do 'I run'.should =~ /run/ end end ``` Then visit `/opal_spec` from your app and **reload at will**.  ## License © 2012-2013 Elia Schito Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions: The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software. THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.