TypeError: Cannot convert undefined or null to object

[jacekwilczynski]

Hi! Let me first say a big thank you for this library - I'm migrating from RHF due to superior DX and typesafety and I'm pretty happy so far.

I'm on v0.34.0. There's one surprise I've encountered: when I did something like this:

form.store.subscribe(() => {
  const { orderItems } = form.state.values;

  // ensure there is at least one draft order item for the user to fill in, unless there can't be any more order items:
  if (orderItems.length === 0 || (!orderItems.at(-1).isDraft && orderItems.length < maxOrderItems))
    form.pushFieldValue('orderItems', createDraftOrderItem());
  }
});

After order item removal with removeFieldValue somewhere else, I get an error when my input component calls field.handleChange. The error is here, because state.meta did not have an errorMap field.

This seems to happen in two cases:

1. With a conditionally rendered field: form.pushFieldValue gets called before <form.Field name="orderItems" type="array"> was ever rendered. Then form.state.fieldMeta.orderItems is {isTouched: true, isBlurred: true, isDirty: true}. This can be resolved by calling form.useField({ name: 'orderItems', mode: 'array" }) right after useForm to make sure the field meta gets set up even if the field has not been rendered yet.
2. When I add two order items and then delete them - the pushFieldValue call doesn't immediately error, but the automatically added order item object is missing some properties and the field meta for one of them is also a partial of proper field meta, like above.. This can be solved by wrapping the listener in setTimeout(..., 0).

Are those bugs or am I doing something wrong? If needed, I can prepare a CodeSandbox and create an issue.