Tiago Ameller PRO said about 2 years ago on The Stimulus 2.0 Tutorial :
As you mention bin/webpack-dev-server, a great enhancement for my rails 6 development I did is using foreman
Put a file called Procfile.dev in your app's home directory:
web: bundle exec puma -p 3000 -C config/puma.rb
webpacker: ./bin/webpack-dev-server
log: tail -f ./log/development.log
and call it to start both rails and webpacker servers:
foreman start -f Procfile.dev
You can restart your server when needed calling: 
touch tmp/restart.txt