I\'m currently trying Rails 6.0.0.rc1 which seems to have moved the default javascript folder from app/assets/javascript to app/javascript
You need to do the following steps to add custom javascript file to rails 6 (webpacker)
1.Create your custom file named custom.js in app/javascript/packs directory.
For testing purpose, write any console.log in it.
// app/javascript/packs/custom.js
console.log("custom js file loaded")
2. Go to your application.html.erb and add the following line at the end of your
<%= javascript_pack_tag 'custom', 'data-turbolinks-track': 'reload' %>
3. Now execute rake assets:precompile
This will pack your javascript code (including our custom file we just added)
Now reload your page and you should see the message
custom js file loaded
in your browser console
Hope it helps :)