React Hook Form defaultValues v/s values

Question

When using React Hook Form, while I understand that the "defaultValues" is used to set the form field values on initial form load.

However, let's say there is a dynamic form with dependent fields e.g. if Dropdown Field 1 is set to "ABC", then Field 2 should be set to "ABC 1 Updated" To handle such use cases, is it possible to "watch" Field 1 and based on it's value, update the "defaultValues" with Field 2 then set to "ABC 1 Updated"

or is it not recommended to update "defaultValues" after the initial form load.

I also see "values" in the below documentation, but haven't seen it's usage much. Other option is doing "setValue". Not sure what is the recommended way of handling side effects with a dynamic form with dependent fields.

https://react-hook-form.com/docs/useform#defaultValues

Answer 1

You should use values if it's dependent on the return of an async function or the field is dynamic. Use defaultValues if the fields are static.

You should never use setValue for updating a field array. This could cause problems in rerendering components. Just put it from values.

values: asynFn ? { ...asyncFn } : defaultValues

Answer 2

Yes, it's not recommended to update "defaultValues".

You can use reset or setValue