Accessing form error array using form.useStore and destructuring can cause react update depth issue

[craigbehnke]

Describe the bug

When using destructuring, the form.useStore hook returns an error array that appears to change on every render. This then causes a react update depth issue.

Your minimal, reproducible example

https://stackblitz.com/edit/tanstack-form-oryfsj?file=README.md

Steps to reproduce

1. Access the errors array using destructuring, like so:

   const {errors}: {errors: ValidationError[]} = form.useStore(state => ({
   errors: state.errors
   }))

2. Use the errors array as a dependency to a react hook, such as useEffect or useMemo
3. Observe that this react hook is perpetually called.

Please see the provided repro.

Expected behavior

As a user, I want the error array to be updated only when the error array changes.

How often does this bug happen?

Every time

Screenshots or Videos

No response

Platform

• OS: MacOS
• Browser: Chrome/Safari
• Typescript/React

TanStack Form adapter

react-form

TanStack Form version

v0.29.1

TypeScript version

5.5.4

Additional context

No response

[jackcoup]

I also get this almost every time I use form.useStore((state) => state.values) really not ideal.

[SiddOnKeys]

did u find a fix or any way around it, its causing issues for me and I'm on a deadline lol

[jackcoup]

I believe I used form.useField() for each prop

[Balastrong]

I'm sorry but const errors = form.useStore((state) => state.errors) seems to be working fine, I think I don't understand where's the problem.

What feature are you trying to implement?

[craigbehnke]

@Balastrong It's been a bit, but what I was trying to achieve was to have 1 hook that would return the errors and other properties, i.e.

// My one hook to rule them all
const {isValid, isPristine, isSubmitted, isSubmitting,errors} = form.useStore(
        state => ({
            canSubmit: state.canSubmit,
            isPristine: state.isPristine,
            isSubmitted: state.isSubmitted,
            isSubmitting: state.isSubmitting,
            errors: state.errors
        })
    )

Because of this bug (and after a extended debugging session) I had to split it into 2 different hook calls so that it would work:

// The main hook
const {isValid, isPristine, isSubmitted, isSubmitting} = form.useStore(
        state => ({
            canSubmit: state.canSubmit,
            isPristine: state.isPristine,
            isSubmitted: state.isSubmitted,
            isSubmitting: state.isSubmitting
        })
    )
// The separate error hook to bypass the bug
const errors = form.useStore(state => state.errors)

[Balastrong]

Ok! I don't have a ready answer sadly, but I understood the issue, thanks :D

[crutchcorn]

This is a complex issue that is understandably a major headache for our users.

While researching a fix, we've also found an issue with how we handle derived state: #1036

Needless to say, we're working on a broader scope fix to this problem rather than a band-aid. This starts with:

https://github.com/TanStack/store/pull/40 And #1038 (via dogfooding https://github.com/TanStack/store/pull/40 )

This might be a larger body of work than anticipated, so please standby while we work hard on making this a reality