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.
Instructions
Create createTransaction(description, amount) and trim the description.
Hint: 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.
Your Code
Describe what you want to build for this step and I'll write the code — then click Apply to drop it into your editor. This step: Create createTransaction(description, amount) and trim the description.