Once I started the project I update the @rails/webpacker npm package from version 5 to version ^6.0.0-pre.2.

Thinking it was the last possible version, which btw it works great on development mode, the problem was when I tried to upload to Heroku (production) I got the following error message:

ERROR in Conflict: Multiple assets emit different content to the same filename js/.br
ERROR in Conflict: Multiple assets emit different content to the same filename .br

I hadn't any idea 💡 what the heck is the .br format, in fact, I haven’t heard anything about it.

After a little bit of research here we have what the .br format is.

At the end, I just update the webpacker version to 6.0.0-beta.7 and now it works as expected in a production environment.

commit

Note: BTW, was fixed up in this PR.

See you next time!