Form validations with HTML5 and modern Rails

Recently I have worked on form-validation systems in a couple of modern Rails apps, and I learned a few things along the way I would like to share.My starting point was:I wanted to use modern Rails: Webpacker, Turbolinks, remote forms and Stimulus.I wanted to leverage standard HTML form validations when they made sense.I wanted to support server-side validations.I wanted to show server-side and client-side validations consistently.I wanted to avoid ad-hoc client-side validation logic like the plague.