-
SurveyJS
Open-Source JSON Form Builder to Create Dynamic Forms Right in Your App. With SurveyJS form UI libraries, you can build and style forms in a fully-integrated drag & drop form builder, render them in your JS app, and store form submission data in any backend, inc. PHP, ASP.NET Core, and Node.js.
These were some interesting example of what this library can do, but of course there is more to it than just this. You can checkout the project on GitHub. Please give it a try, the readme should provide a pretty decent getting started. If you feel that some features are missing or that there is a bug, please do not hesitate to create on issue or create a PR, I welcome contributions. ;-)
ngx-errors
All of these examples have one thing in common; they require boilerplate code. While I'd say that it should not be needed. We can create a directive that binds to the formControl and when the formControl is invalid then it can show the error message. Even better, it can render the error message using a translation library like transloco or ngx-translate.