Getting SyntaxError in javascript/application.js when setting rails project to use importmaps

Question

I'm trying to move a rails 7 project from using esbuild to using importmaps and getting the following error:

// app/javascript/application.js import '@hotwired/turbo-rails'; // <-- Uncaught SyntaxError: Cannot use import statement outside a module import 'controllers'; 

I've run and rerun bundle exec rails importmap:install a bunch of times already and compared all relevant files that I know of with a project where importmaps work.

For obvious reasons, adding "type": "module", to package.json is not an option (I don't have a package.json).

Am I missing something?

Answer 1

Shamefully posting the solution in case anyone ever runs into the same problem:

We're using namespaces in the project and I forgot to include the javascript_importmap_tags tag in every namespaced layout file.