What defaultValues default value can I use for an optional Date field?

[tibbe]

I have an optional Date field using a custom date picker component (in React Native). What's the correct default value to set for this field in defaultValues? Using undefined isn't recommended. Since isDirty depends on a comparison between the actual values and the default values I do need some sort of default value (see #3213).

[Moshyfawn]

Does null work for you?

[tibbe]

Does null work for you?

Maybe. The question is really "what's commonly used?" or "what's best practice?". Optional fields seem like something that would be common but I have seen no docs around it, except those saying that default values can't be undefined (which would be a natural way to model optional fields in JavaScript).

[Moshyfawn]

undefined is sort of a reserved value in React. When it comes to the concept of controlled vs uncontrolled inputs in React, if you pass undefined to your input and later updated to a non-undefined value, you'll get a React warning "you can't mix controlled & uncontrolled inputs".

[Moshyfawn]

null is commonly used to supply an "empty" value to a number or a Date type of input.

[Moshyfawn]

For text inputs - an empty string is a good default; it follows the native HTML input conventions. Since RHF supports both controlled & uncontrolled inputs - following the Web standard of handling inputs is beneficial.

[tibbe]

Thanks for the explanation. To close the circle I think using undefined is more common in React Native, which I'm using, especially when representing missing values in custom components (as we're not tied to whatever HTML does). I will use null.