---
description: File-structure conventions for design-system components
globs: app/components/**/*.{ts,tsx}
alwaysApply: false
---

# Component file structure

## Split-file pattern (default)

Anything in `app/components/controls/**` and `app/components/utility/**` uses
a **4-file split**, one folder per component:

```
app/components/controls/<Name>/
  <Name>.types.ts        // Public Props + internal ViewProps
  <Name>.view.tsx        // "use client"; pure render; exports memo(view)
  <Name>.container.tsx   // "use client"; memo; prop normalization & logic
  index.tsx              // re-exports default + public types
```

**Container** (`<Name>.container.tsx`):

- Marked `"use client"`.
- Receives `<Name>Props`; normalizes PascalCase enums via
  `lib/propNormalization.ts`; computes derived state (clamps, ids, bounds).
- Renders `<<Name>View />` with already-normalized `<Name>ViewProps`.
- Default export: `memo(<Name>Container)` with `.displayName = "<Name>"`.

**View** (`<Name>.view.tsx`):

- Marked `"use client"`.
- Pure render of `<Name>ViewProps`. No prop normalization, no data fetching,
  no derived business logic.
- Default export: `memo(<Name>View)` with
  `.displayName = "<Name>View"`.

**Types** (`<Name>.types.ts`):

- Export `<Name>Props` (consumer-facing, accepts PascalCase + lowercase).
- Export `<Name>ViewProps` (already-normalized shape the view consumes).
- Export any locally-defined value types (`<Name>SizeValue`, etc.).

**Index** (`index.tsx`):

```typescript
export { default } from "./<Name>.container";
export type { <Name>Props } from "./<Name>.types";
```

## Single-file pattern (exception)

`app/components/buttons/*.tsx` and other trivially-presentational components
can stay as a single file when they have **no enum prop normalization and no
derived state** (e.g. `Button.tsx`, `InlineTextButton.tsx`). If you find
yourself adding state, enum normalization, or more than a handful of props,
promote it to the split pattern.

## Wrapper / group components

Related composites live in a **sibling folder**, not inside the base
component's folder — mirror `CheckboxGroup/` ↔ `Checkbox/`,
`IncrementerBlock/` ↔ `Incrementer/`, etc. Each gets its own 4-file split.
Consumers import from the folder's `index.tsx`.