Validation and error handling
Protect the ledger from bad input
Real users mistype, paste spaces, and leave fields empty. Production code treats that as expected behavior. A validation function either returns a clean transaction or throws a precise error. The submit handler catches it and shows a useful message.
Never silently turn invalid money into zero. Invalid is not empty, and empty is not zero.
Instruções
Create createTransaction(description, amount) and trim the description.
Dica: const cleanDescription = description.trim();
Reject a short description and non-positive or non-finite amount.
Wrap transaction creation in try/catch.
Show the error message in #form-error.
Seu Código
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