Bundlebun bundles Bun, and a tour of asset pipelines and JavaScript runtimes Rails has been through

Bundlebun is a Ruby gem that packages the Bun JavaScript runtime, package manager, and bundler directly into a Rails project's Gemfile. This eliminates the need for separate Node.js installation, Docker, or version managers, ensuring every developer gets the exact same Bun version after running `bundle install`. The post also provides a comprehensive history of Rails asset pipelines from Rails 2 through Rails 8, covering Sprockets, Webpacker, importmap-rails, and the #nobuild movement, explaining why #nobuild has real limitations for apps using modern JavaScript ecosystems (TypeScript, JSX, npm packages). Bundlebun integrates with vite-ruby, jsbundling-rails, cssbundling-rails, and ExecJS, and features automatic gem releases tied to Bun releases via GitHub Actions cron jobs.