Ruby on Rails – Javascript(s) Folder and Application.js Missing

1. Identify Your JavaScript Setup:

• Importmap: Look for config/importmap.rb. Add JavaScript to app/javascript/application.js.
• esbuild or Webpack: Look for package.json. JavaScript goes in app/javascript/application.js.

2. Set Up JavaScript (if missing):

• For Importmap: Run rails importmap:install.
• For esbuild: Run rails javascript:install:esbuild.
• For Webpacker: Run rails webpacker:install.

Include JavaScript in Layout:

Add this to application.html.erb:

<%= javascript_importmap_tags %> <!-- For Importmap -->
or
<%= javascript_include_tag "application", defer: true %> <!-- For esbuild/Webpacker -->