Cannot find module '@rails/ujs' - Rails 6 Webpack App

Question

I have these errors in a Rails 6 app and all javascript is not working:

ERROR in ./app/javascript/packs/application.js
Module not found: Error: Can't resolve '@rails/activestorage' in '/Users/jrsahuquillo/Dropbox/myappname/app/javascript/packs'
 @ ./app/javascript/packs/application.js 9:0-31

ERROR in ./app/javascript/packs/application.js
Module not found: Error: Can't resolve '@rails/ujs' in '/Users/jrsahuquillo/Dropbox/myappname/app/javascript/packs'
 @ ./app/javascript/packs/application.js 5:0-21

My package.json is:

{
  "name": "myappname",
  "private": true,
  "dependencies": {
    "@rails/actioncable": "^6.0.0-alpha",
    "@rails/activestorage": "^6.0.2",
    "@rails/ujs": "^6.0.2",
    "@rails/webpacker": "4.2.0",
    "bootstrap": "^4.4.1",
    "jquery": "^3.4.1",
    "jquery-ui": "^1.12.1",
    "jquery-ui-dist": "^1.12.1",
    "popper.js": "^1.16.0",
    "serialize-javascript": "2.1.2",
    "turbolinks": "^5.2.0"
  },
  "version": "0.1.0",
  "devDependencies": {
    "webpack-dev-server": "^3.8.0"
  },
  "optionalDependencies": {
    "fsevents": "2.0.0"
  }
}

In application.js:

require("@rails/ujs").start();
require("turbolinks").start();
require("@rails/activestorage").start();
require("channels");
require("bootstrap/dist/js/bootstrap");

In app/views/layouts/application.html.erb:

<%= stylesheet_link_tag 'application', media: 'all', 'data-turbolinks-track': 'reload' %>
<%= stylesheet_pack_tag 'application', media: 'all', 'data-turbolinks-track': 'reload' %>
<%= javascript_pack_tag 'application', 'data-turbolinks-track': 'reload' %>

It was working ok, but I don´t know when and why it left working. Could someone help me?

Answer 1

Sorry, I solved it yet. Previously to having the error, I installed yarn autoclean, and I discovered later that in .yarnclean there was this:

# asset directories
docs
doc
website
images
assets

I removed this, and error disappeared.