Initial value should not be undefined

[punkpeye]

Describe the bug and the expected behavior

const [form, fields] = useForm({
  defaultValue: {
    message: '',
  },
  lastResult: fetcher.data?.submission,
  onSubmit: (event, { action, formData, method }) => {
    event.preventDefault();

    fetcher.submit(formData, {
      action,
      method,
    });

    historyState.set('');

    messageInputControl.change('');

    setShowTip(false);
  },
});

const [inputFocused, setInputFocused] = useState<boolean>(false);

const formRef = useRef<HTMLFormElement>(null);

const messageInputControl = useInputControl(fields.message);

useEffect(() => {
  console.log('???', messageInputControl.value);
});

Conform version

v1.2.2

Steps to Reproduce the Bug or Issue

This prints:

??? undefined
??? undefined
??? undefined
???
???

The first couple of undefined value are unexpected, since the value of the input is known from the start (it is set in defaultValue).

What browsers are you seeing the problem on?

Chrome

Screenshots or Videos

No response

Additional context

No response

[punkpeye]

Actually, this seems like a problem with fields.message – initialValue property is undefined initially, despite there being a default.

[punkpeye]

Digging deeper, it looks like it is specific to empty string value.

If I set defaultValue to:

defaultValue: {
  message: 'foo',
},

it behaves as expected. It is only when message: '' that it breaks.

[edmundhung]

What you see is a side effect of conform normalising the default value for the ease of dirty checking. 😅

This means empty value and empty array are always transformed to undefined.

I do plan to fix this. But I am afraid some people might have already relied on such behaviour. So I am leaning towards fixing it in the next major version instead.

[lifeiscontent]

@edmundhung any ideas on when that work might happen? just ran into this today 😅

[goamaan]

I'm facing this same problem with a checkbox/switch field being initialized with false but meta.initialValue is undefined still