Adding validation check to `handleSubmit`.
Adding validation check to `handleSubmit`.

Also adding `e.preventDefault()` and changing to plain `return`.
Capocaccia/reacting,lewiscowper/serviceworker-demo,nfelix/primeNameChecker,Capocaccia/reacting,lewiscowper/serviceworker-demo,nicrocs/react-form-builder,nicrocs/react-form-builder,nfelix/primeNameChecker