React Hook Form Best Practices

Comprehensive performance optimization guide for React Hook Form applications. Contains 41 rules across 8 categories, prioritized by impact to guide form development, automated refactoring, and code generation.

When to Apply

Reference these guidelines when:

• Writing new forms with React Hook Form
• Configuring useForm options (mode, defaultValues, validation)
• Subscribing to form values with watch/useWatch
• Integrating controlled UI components (MUI, shadcn, Ant Design)
• Managing dynamic field arrays with useFieldArray
• Reviewing forms for performance issues

Rule Categories by Priority

formcfg-

sub-

ctrl-

valid-

array-

formstate-

integ-

adv-

Quick Reference

1. Form Configuration (CRITICAL)

• formcfg-validation-mode

  - Use onSubmit mode for optimal performance

• formcfg-revalidate-mode

  - Set reValidateMode to onBlur for post-submit performance

• formcfg-default-values

  - Always provide defaultValues for form initialization

• formcfg-async-default-values

  - Use async defaultValues for server data

• formcfg-should-unregister

  - Enable shouldUnregister for dynamic form memory efficiency

• formcfg-useeffect-dependency

  - Avoid useForm return object in useEffect dependencies

2. Field Subscription (CRITICAL)

• sub-usewatch-over-watch

  - Use useWatch instead of watch for isolated re-renders

• sub-watch-specific-fields

  - Watch specific fields instead of entire form

• sub-usewatch-with-getvalues

  - Combine useWatch with getValues for timing safety

• sub-deep-subscription

  - Subscribe deep in component tree where data is needed

• sub-avoid-watch-in-render

  - Avoid calling watch() in render for one-time reads

• sub-usewatch-default-value

  - Provide defaultValue to useWatch for initial render

• sub-useformcontext-sparingly

  - Use useFormContext sparingly for deep nesting

3. Controlled Components (HIGH)

• ctrl-usecontroller-isolation

  - Use useController for re-render isolation

• ctrl-avoid-double-registration

  - Avoid double registration with useController

• ctrl-controller-field-props

  - Wire Controller field props correctly for UI libraries

• ctrl-single-usecontroller-per-component

  - Use single useController per component

• ctrl-local-state-combination

  - Combine local state with useController for UI-only state

4. Validation Patterns (HIGH)

• valid-resolver-caching

  - Define schema outside component for resolver caching

• valid-dynamic-schema-factory

  - Use schema factory for dynamic validation

• valid-error-message-strategy

  - Access errors via optional chaining or lodash get

• valid-inline-vs-resolver

  - Prefer resolver over inline validation for complex rules

• valid-delay-error

  - Use delayError to debounce rapid error display

• valid-native-validation

  - Consider native validation for simple forms

5. Field Arrays (MEDIUM-HIGH)

• array-use-field-id-as-key

  - Use field.id as key in useFieldArray maps

• array-complete-default-objects

  - Provide complete default objects for field array operations

• array-separate-crud-operations

  - Separate sequential field array operations

• array-unique-fieldarray-per-name

  - Use single useFieldArray instance per field name

• array-virtualization-formprovider

  - Use FormProvider for virtualized field arrays

6. State Management (MEDIUM)

• formstate-destructure-formstate

  - Destructure formState properties before render

• formstate-useformstate-isolation

  - Use useFormState for isolated state subscriptions

• formstate-getfieldstate-for-single-field

  - Use getFieldState for single field state access

• formstate-subscribe-to-specific-fields

  - Subscribe to specific field names in useFormState

• formstate-avoid-isvalid-with-onsubmit

  - Avoid isValid with onSubmit mode for button state

7. Integration Patterns (MEDIUM)

• integ-shadcn-form-import

  - Verify shadcn Form component import source

• integ-shadcn-select-wiring

  - Wire shadcn Select with onValueChange instead of spread

• integ-mui-controller-pattern

  - Use Controller for Material-UI components

• integ-value-transform

  - Transform values at Controller level for type coercion

8. Advanced Patterns (LOW)

• adv-formprovider-memo

  - Wrap FormProvider children with React.memo

• adv-devtools-performance

  - Disable DevTools in production and during performance testing

• adv-testing-wrapper

  - Create test wrapper with QueryClient and AuthProvider

How to Use

Read individual reference files for detailed explanations and code examples:

• Section definitions - Category structure and impact levels
• Rule template - Template for adding new rules
• Reference files:

  references/{prefix}-{slug}.md

Related Skills

• For schema validation with Zod resolver, see

  zod

  skill
• For React 19 server actions, see

  react-19

  skill
• For UI/UX form design, see

  frontend-design

  skill

Full Compiled Document

For the complete guide with all rules expanded:

AGENTS.md