React Render Types — Composition Patterns

Patterns for building React components with @renders type annotations. Covers design system primitives, app-level composition, and advanced techniques.

Annotation Syntax Quick Reference

@renders {X}           Required — must return X
@renders? {X}          Optional — may return X or null
@renders* {X}          Many — zero or more X
@renders! {X}          Unchecked — declares X, skips return validation
@renders {A | B}       Union — must return A or B
@renders {MyAlias}     Type alias — resolves type MyAlias = A | B at lint time
@transparent           Wrapper — plugin looks through to validate children
                       (or use additionalTransparentComponents setting for built-ins)

Pattern Categories

Priority	Category	When to read
1	Design System Patterns	Building constrained component APIs
2	Wrapper Patterns	Creating transparent or conditional wrappers
3	App Composition Patterns	Consuming a design system in app layouts
4	Advanced Patterns	Unions, chains, dynamic rendering, expressions

Design System Patterns

Core patterns for building component libraries with enforced composition.

• constrained-children — Restrict children to specific component types (Menu → MenuItem)
• typed-slot-props — Enforce types on named slot props (header, footer, sidebar)
• component-variants — Create specialized variants that satisfy a base render type

Read detailed examples: references/patterns/design-system.md

Wrapper Patterns

Patterns for components that wrap other content without breaking composition.

• transparent-wrappers — Mark layout/styling wrappers with @transparent
• conditional-rendering — Use @renders? and @renders* for optional/repeated content

Read detailed examples: references/patterns/wrappers.md

App Composition Patterns

Patterns for building app-level layouts that consume design system components.

• page-layouts — Compose pages with typed header/content/footer slots
• dashboard-composition — Build dashboards with constrained card/widget areas
• navigation-structure — Typed sidebar/nav with enforced nav item types

Read detailed examples: references/patterns/app-composition.md

Advanced Patterns

Techniques for complex scenarios.

• union-types — Accept multiple component types in a single slot
• type-aliases — Define reusable type unions for @renders annotations
• render-chains — Satisfy render types transitively through intermediate components
• unchecked-escape-hatch — Use @renders! for dynamic rendering the plugin can't analyze
• expression-analysis — Ternary, logical AND, and .map() in annotated returns

Read detailed examples: references/patterns/advanced.md

Choosing the Right Modifier

Can the slot be empty?
├── No → Must always render something
│   ├── Exactly one component → @renders {X}
│   └── One of several types  → @renders {A | B}
└── Yes
    ├── Zero or one component  → @renders? {X}
    └── Zero or more instances → @renders* {X}

Can the plugin analyze the return?
├── Yes → use the modifier above
└── No (dynamic/registry) → add ! → @renders! {X}, @renders?! {X}, @renders*! {X}