rollup.js for Rails

Use rollup.js to bundle your JavaScript, then deliver it via the asset pipeline in Rails. This gem provides an installer to get you going with rollup in a new Rails application, and a convention to use app/assets/builds to hold your bundled output as artifacts that are not checked into source control (the installer adds this directory to .gitignore by default).

You develop using this approach by running rollup.js in watch mode in a terminal with yarn build --watch (and your Rails server in another, if you're not using something like puma-dev). Whenever rollup.js detects changes to any of the JavaScript files in your project, it'll bundle app/javascript/application.js into app/assets/builds/javascript.js. You can refer to the build output in your layout using the standard asset pipeline approach with <%= javascript_include_tag "application" %>.

When you deploy your application to production, rollup.js attaches to the assets:precompile task to ensure that all your package dependencies from package.json have been installed via npm, and then runs yarn build to process app/javascript/application.js into app/assets/builds/javascript.js. The latter file is then picked up by the asset pipeline, digested, and copied into public/assets, as any other asset pipeline file.

This also happens in testing where rollup attaches to the test:prepare task to ensure the JavaScript has been compiled before testing commences. (Note that this currently only applies to rails test:* tasks (like test:all or test:controllers), not "rails test", as that doesn't load test:prepare).

That's it!

You can tailor the configuration of rollup.js through the rollup.config.js that's created in the root of your project by the installer.

Installation

You must already have node and yarn installed on your system. Then:

  1. Add rollupjs-rails to your Gemfile with gem 'rollupjs-rails'
  2. Run ./bin/bundle install
  3. Run ./bin/rails rollup:install

Or, in Rails 7+, you can preconfigure your new application to use rollup.js with rails new myapp -j rollup.

The sister gem to esbuild-rails

This gem is almost identical in setup and purpose to esbuild-rails, which follows the same conventions, but uses esbuild instead.

License

rollup.js for Rails is released under the MIT License.