json-render/.changeset/shadcn-and-event-handles.md

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"@json-render/core": minor "@json-render/react": minor

"@json-render/shadcn": minor

New @json-render/shadcn package, event handles, built-in actions, and stream improvements.

New: @json-render/shadcn Package

Pre-built shadcn/ui component library for json-render. 30+ components built on Radix UI + Tailwind CSS, ready to use with defineCatalog and defineRegistry.

• shadcnComponentDefinitions — Zod-based catalog definitions for all components (server-safe, no React dependency via @json-render/shadcn/catalog)
• shadcnComponents — React implementations for all components
• Layout: Card, Stack, Grid, Separator
• Navigation: Tabs, Accordion, Collapsible, Pagination
• Overlay: Dialog, Drawer, Tooltip, Popover, DropdownMenu
• Content: Heading, Text, Image, Avatar, Badge, Alert, Carousel, Table
• Feedback: Progress, Skeleton, Spinner
• Input: Button, Link, Input, Textarea, Select, Checkbox, Radio, Switch, Slider, Toggle, ToggleGroup, ButtonGroup

New: Event Handles (on())

Components now receive an on(event) function in addition to emit(event). The on() function returns an EventHandle with metadata:

• emit() — fire the event
• shouldPreventDefault — whether any action binding requested preventDefault
• bound — whether any handler is bound to this event

New: BaseComponentProps

Catalog-agnostic base type for component render functions. Use when building reusable component libraries (like @json-render/shadcn) that are not tied to a specific catalog.

New: Built-in Actions in Schema

Schemas can now declare builtInActions — actions that are always available at runtime and automatically injected into prompts. The React schema declares setState, pushState, and removeState as built-in, so they appear in prompts without needing to be listed in catalog actions.

New: preventDefault on ActionBinding

Action bindings now support a preventDefault boolean field, allowing the LLM to request that default browser behavior (e.g. navigation on links) be prevented.

Improved: Stream Transform Text Block Splitting

createJsonRenderTransform() now properly splits text blocks around spec data by emitting text-end/text-start pairs. This ensures the AI SDK creates separate text parts, preserving correct interleaving of prose and UI in message.parts.

Improved: defineRegistry Actions Requirement

defineRegistry now conditionally requires the actions field only when the catalog declares actions. Catalogs with no actions (e.g. actions: {}) no longer need to pass an empty actions object.