function App() { const form = useForm({ defaultValues: { firstName: '', lastName: '', }, onSubmit: async ({ value }) => { console.log(value) }, })

return ( <form onSubmit={(e) => { e.preventDefault() e.stopPropagation() form.handleSubmit() }} > <form.Field name="firstName" validators={{ onChange: ({ value }) => !value ? 'Required' : value.length < 3 ? 'Too short' : undefined, }} children={(field) => ( <> <input value={field.state.value} onBlur={field.handleBlur} onChange={(e) => field.handleChange(e.target.value)} /> {!field.state.meta.isValid && ( {field.state.meta.errors.join(', ')} )} </> )} /> <form.Subscribe selector={(state) => [state.canSubmit, state.isSubmitting]} children={([canSubmit, isSubmitting]) => ( {isSubmitting ? '...' : 'Submit'} )} /> ) }


### Production Setup (Recommended)

For production apps, use `createFormHook` to pre-bind reusable UI components and reduce boilerplate:

```tsx
import { createFormHookContexts, createFormHook } from '@tanstack/react-form'
import { TextField, NumberField, SubmitButton } from '~/ui-library'

const { fieldContext, formContext } = createFormHookContexts()

export const { useAppForm } = createFormHook({
  fieldComponents: { TextField, NumberField },
  formComponents: { SubmitButton },
  fieldContext,
  formContext,
})

Devtools

npm install -D @tanstack/react-devtools @tanstack/react-form-devtools

import { TanStackDevtools } from '@tanstack/react-devtools'
import { formDevtoolsPlugin } from '@tanstack/react-form-devtools'

<TanStackDevtools
  config={{ hideUntilHover: true }}
  plugins={[formDevtoolsPlugin()]}
/>

Rule Categories

Priority	Category	Rule File	Impact
CRITICAL	Form Setup	`rules/form-setup.md`	Correct form creation and type inference
CRITICAL	Validation	`rules/val-validation.md`	Prevents invalid submissions and poor UX
CRITICAL	Schema Validation	`rules/val-schema-validation.md`	Type-safe validation with Zod/Valibot/ArkType
HIGH	Form Composition	`rules/comp-form-composition.md`	Reduces boilerplate, enables reusable components
HIGH	Field State	`rules/field-state.md`	Correct state access and reactivity
HIGH	Array Fields	`rules/arr-array-fields.md`	Dynamic list management
HIGH	Linked Fields	`rules/link-linked-fields.md`	Cross-field validation (e.g. confirm password)
MEDIUM	Listeners	`rules/listen-listeners.md`	Side effects on field events
MEDIUM	Submission	`rules/sub-submission.md`	Correct submit handling and meta passing
MEDIUM	SSR / Meta-Frameworks	`rules/ssr-meta-frameworks.md`	Server validation with Start/Next.js/Remix
LOW	UI Libraries	`rules/ui-libraries.md`	Headless integration with component libraries

Critical Rules

Always Do

Type from defaultValues — never pass generics to useForm<T>(), let TS infer from defaultValues
Prevent default on submit — e.preventDefault(); e.stopPropagation(); form.handleSubmit()
Use children render prop — form.Field uses render props via children={(field) => ...}
Use form.Subscribe with selector — subscribe to specific state slices to avoid re-renders
Use useStore with selector — useStore(form.store, (s) => s.values.name) not useStore(form.store)
Use createFormHook in production — pre-bind components for consistency and less boilerplate
Debounce async validators — set onChangeAsyncDebounceMs or asyncDebounceMs

Never Do

Pass generics — useForm<MyType>() breaks the design; use typed defaultValues instead
Skip e.preventDefault() — native form submission will bypass TanStack Form's handling
Use useField for reactivity — use useStore(form.store) or form.Subscribe instead
Omit selector in useStore — causes full re-render on every state change
Use type="reset" without e.preventDefault() — native reset bypasses TanStack Form; use form.reset() explicitly
Expect transformed values in onSubmit — Standard Schema transforms aren't applied; parse manually in onSubmit

Key Patterns

// Schema validation (form-level with Zod)
const form = useForm({
  defaultValues: { age: 0, name: '' },
  validators: {
    onChange: z.object({ age: z.number().min(13), name: z.string().min(1) }),
  },
  onSubmit: ({ value }) => console.log(value),
})

// Array fields
<form.Field name="hobbies" mode="array" children={(field) => (
  <div>
    {field.state.value.map((_, i) => (
      <form.Field key={i} name={`hobbies[${i}].name`} children={(sub) => (
        <input value={sub.state.value} onChange={(e) => sub.handleChange(e.target.value)} />
      )} />
    ))}
    <button type="button" onClick={() => field.pushValue({ name: '' })}>Add</button>
  </div>
)} />

// Linked fields (confirm password)
<form.Field name="confirm_password" validators={{
  onChangeListenTo: ['password'],
  onChange: ({ value, fieldApi }) =>
    value !== fieldApi.form.getFieldValue('password') ? 'Passwords do not match' : undefined,
}} children={(field) => <input value={field.state.value} onChange={(e) => field.handleChange(e.target.value)} />} />

// Listeners (reset province when country changes)
<form.Field name="country" listeners={{
  onChange: ({ value }) => { form.setFieldValue('province', '') },
}} children={(field) => <input value={field.state.value} onChange={(e) => field.handleChange(e.target.value)} />} />

// Form composition with withForm
const ChildForm = withForm({
  defaultValues: { firstName: '', lastName: '' },
  render: function Render({ form }) {
    return <form.AppField name="firstName" children={(field) => <field.TextField label="First Name" />} />
  },
})

tanstack-form

TanStack Form

Quick Setup