In that case, you can simply empty your browser cache or call directly the address_to_your_awesome_app/#/index.html to force the reload of the HTML page that contains the main.dart.js file.
This is just for testing environments and will not work consistently in production. For that, you’ll have to control caching on the server-side when you serve your files.
Your issue might originate from the new flutter_service_worker.js. You can remove the Service Worker temporarily or modify it if its caching strategy puts a break on your development flow.