Why does register not support defaultValue?

[timkindberg]

Hello thank you for the awesome library!! We are migrating from Formik.

We are wondering though, why doesn't register support defaultValue? I am really loving defining all of my fields in their own isolated components, with validation logic and initial values all co-located. I'd rather not specify the defaultValue at the form level.

I've found that if I declare register in conjunction with resetField I can achieve a defaultValue. Like this:

  const field = React.useMemo(() => {
    const field = register("firstName");
    resetField("firstName", { defaultValue: "Tim" });
    return field;
  }, []);

Code Sandbox:
https://codesandbox.io/s/useformstate-forked-t7b0gq?file=/src/App.js:472-657

Is there a problem with this approach? Or could the same thing be done internally to add support for defaultValue to register?

In general I'm also wondering why not balance the APIs of register and useController. It seems it could be achieved and then have more predictable usage. Saw a discussion about this here: #4542

Update: It even works when the registered field is watched, it has the defaultValue. But only if the watched field is mounted first. Is this restriction the reason that defaultValue was removed from register?

[bluebill1049]

because defaultValue belongs to inputs eg <input defaultValue="test" /> and register already capture a lot props and prefer to leave those native attributes to the input itself, if you have issue with that you can always provide default value at useForm

[timkindberg]

Is it technically achievable to allow the defaultValue to be set at the field level? I'm not talking just about passing defaultValue to the input, but more like how it works if you pass to useForm. The reason I ask is because I really like decoupling my fields from the form and declare them in isolation. Thank you for the quick response!!