Add Hook

Guide for adding a new hook to the shadcn-hooks project. The source of truth is src/registry/hooks/. The packages/shadcn-hooks/ directory is auto-generated and should NOT be edited manually. Do NOT run any sync command as part of this skill; the user will run it manually when needed.

Checklist

Copy this checklist and track progress:

Add Hook: use-<name>
- [ ] Step 1: Create registry entry (src/registry/hooks/use-<name>/)
- [ ] Step 2: Register in meta.json
- [ ] Step 3: Update introduction.mdx
- [ ] Step 4: Create skill reference doc
- [ ] Step 5: Update skill SKILL.md function table
- [ ] Step 6: Verify (lint + test)

Step 1: Create Registry Entry

Create directory src/registry/hooks/use-<name>/ with 5 files:

1a. index.ts — Hook implementation

Rules:

• Use @/registry/hooks/... and @/registry/lib/... import aliases
• Named export: export function use<Name>(...)
• Export all public types from the same file
• TypeScript strict, no any
• Reuse existing hooks where possible (e.g. useBoolean, useEventListener, useMemoizedFn)

Reference example — simple hook:

// src/registry/hooks/use-previous/index.ts
import { useRef } from 'react'

export type ShouldUpdateFunc<T> = (prev?: T, next?: T) => boolean
const defaultShouldUpdate = <T>(a?: T, b?: T) => !Object.is(a, b)

export default function usePrevious<T>(
  state: T,
  shouldUpdate: ShouldUpdateFunc<T> = defaultShouldUpdate,
): T | undefined {
  const prevRef = useRef<T>()
  const curRef = useRef<T>()

  if (shouldUpdate(curRef.current, state)) {
    prevRef.current = curRef.current
    curRef.current = state
  }

  return prevRef.current
}

Reference example — hook composing other hooks:

// src/registry/hooks/use-hover/index.ts
import { useBoolean } from '@/registry/hooks/use-boolean'
import { useEventListener } from '@/registry/hooks/use-event-listener'
import type { BasicTarget } from '@/registry/lib/create-effect-with-target'

export interface UseHoverOptions {
  onEnter?: () => void
  onLeave?: () => void
  onChange?: (isHovering: boolean) => void
}

export function useHover(
  target: BasicTarget,
  options?: UseHoverOptions,
): boolean {
  const { onEnter, onLeave, onChange } = options || {}
  const [state, { setTrue, setFalse }] = useBoolean(false)
  useEventListener(
    'mouseenter',
    () => {
      onEnter?.()
      setTrue()
      onChange?.(true)
    },
    { target },
  )
  useEventListener(
    'mouseleave',
    () => {
      onLeave?.()
      setFalse()
      onChange?.(false)
    },
    { target },
  )
  return state
}

1b. registry-item.json — Dependencies

{
  "registryDependencies": ["@hooks/use-dependency-a", "@hooks/use-dependency-b"]
}

• List all hooks/libs this hook depends on, prefixed with @hooks/
• If no dependencies: { "registryDependencies": [] }

1c. demo/demo-01.tsx — Demo component

'use client'
import { use<Name> } from '..'

export function Demo01() {
  // Interactive demo showcasing the hook
}

Rules:

• Must be a client component ('use client')
• Import hook from '..' (parent directory)
• Use shadcn UI components from ~/components/ui/... (e.g. Button, Card, Input)
• Demo should be interactive and clearly show the hook's behavior

1d. index.mdx — Documentation page

---
title: use<Name>
description: A hook to <description>
---

import { Demo01 } from './demo/demo-01'

<Demo01 />

## Installation

<Tabs items={['CLI', 'Manual']}>
  <Tab>
    <InstallCLI value='use-<name>' />
  </Tab>
  <Tab>
    Copy and paste the following code into your project.
    <RegistrySourceCode value='use-<name>' />
  </Tab>
</Tabs>

## API

\`\`\`ts
// Full type declarations here
\`\`\`

## Credits

- [use-<name>](credit-link)

Notes:

• If the hook has internal dependencies, add multiple <RegistrySourceCode> entries under the Manual tab (see use-boolean which includes use-toggle)
• The API section should contain full TypeScript type declarations

1e. index.test.ts — Tests

import { act, renderHook } from '@testing-library/react'
import { describe, expect, it } from 'vitest'
import { use<Name> } from './index'

describe('use<Name>', () => {
  it('should ...', () => {
    const { result } = renderHook(() => use<Name>(...))
    expect(result.current).toBe(...)
  })
})

Rules:

• Use vitest + @testing-library/react
• Import from './index'
• Cover: default behavior, state changes, edge cases, callbacks
• For DOM-based hooks, create elements in beforeEach / clean up in afterEach

Step 2: Register in meta.json

Add "use-<name>" to src/registry/hooks/meta.json under the appropriate category:

• ---State--- — state management hooks
• ---Advanced--- — memoization, refs, advanced patterns
• ---Lifecycle--- — effects, timers, mount/unmount
• ---Browser--- — DOM, events, browser APIs
• ---Dev--- — development/debug utilities
• ---External--- — wrappers around external libraries

Step 3: Update Introduction Page

Add the new hook to content/docs/introduction.mdx under the appropriate category section:

• State Management — state management hooks
• Advanced — memoization, refs, advanced patterns
• Lifecycle & Effects — effects, timers, mount/unmount
• Browser — DOM, events, browser APIs
• Dev — development/debug utilities
• External Libraries — wrappers around external libraries

Add a line in alphabetical order within the category:

- [`use<Name>`](/docs/hooks/use-<name>) - <Short description>

Step 4: Create Skill Reference

Create skills/shadcn-hooks/references/use<Name>.md:

# use<Name>

<One-line description>.

## Usage

\`\`\`tsx
import { use<Name> } from '@/hooks/use-<name>'

function Component() {
// Minimal usage example
}
\`\`\`

## Type Declarations

\`\`\`ts
// Full type signatures
\`\`\`

## Parameters

| Parameter | Type | Default | Description |
| --------- | ---- | ------- | ----------- |
| ...       | ...  | ...     | ...         |

## Returns

| Type | Description |
| ---- | ----------- |
| ...  | ...         |

Step 5: Update Skill Function Table

Add an entry to the appropriate category table in skills/shadcn-hooks/SKILL.md:

| [`use<Name>`](references/use<Name>.md) | <description> | AUTO |

• Use AUTO for standalone hooks
• Use EXTERNAL for hooks that wrap external npm packages

Step 6: Verify

1. Run linter: check edited files for lint errors
2. Run tests: pnpm test run src/registry/hooks/use-<name>/index.test.ts
3. Verify the dev server renders the doc page correctly (if running)
4. Do not modify packages/shadcn-hooks/ and do not run pnpm run sync or pnpm --dir packages/shadcn-hooks sync; leave that step to the user

Notes

• packages/shadcn-hooks/ is auto-generated. Never edit files in that directory manually as part of this skill.
• Do not execute any sync command from this skill. The user will run sync manually after reviewing the changes.
• packages/shadcn-hooks/src/index.ts exports are also auto-managed — no manual editing needed.