json-render Updates & Release Notes

New Features

TanStack Start renderer: Added @json-render/tanstack-start for JSON-defined applications with file-based routes, reusable layouts, SSR loaders, head metadata, prerender paths, client navigation, and route fallbacks (#334)

Experimental Jev composition: Added experimental_composeSpec and experimental_createEvaluator to compose validated specs from app-owned candidates, plus a Jev model option and iterative composition editing in the playground

Improvements

Vue named slots: Vue registries now support catalog-declared named slots alongside the default children slot (#323)

React streaming stability: Stabilized streamed React renders and added coverage for incomplete streamed props and nested prop identities (#325)

Documentation and project status: Expanded renderer, Jev, and package documentation and added Labs status badges to the project README

Contributors

@ctate

@Railly

New Features

Named slots for React: Components can declare named slots such as header and footer, while children remains the default slot. Slots are preserved through validation, streaming, nested conversion, code export, playground views, and Devtools navigation (#320). Built from the original contribution by @wotnak in #105

Nested repeats: repeat.statePath now accepts item-relative paths such as { "$item": "employees" }, enabling nested data rendering across React, React Native, React Email, React PDF, Image, Ink, Solid, Svelte, and Vue (#319). Built from the original contribution by @tmchow in #256

Harness chat example: Added a complete Next.js example using the AI SDK 7 harness adapter, agent delegation, sandbox transport, and json-render components (#302)

Bug Fixes

Chained action params: Named onSuccess and onError actions now receive their configured params across core and all renderer bridges (#307)

Consistent optional visibility: Element visible fields now remain optional across Zod 4 versions, while prompts explicitly require children arrays for every element (#299)

Spec validation and autofix: Dangling child references are pruned, malformed visibility conditions are reported, and repeated items can be filtered safely (#300)

Improvements

Release toolchain hardening: The workspace now requires Node.js 24 and pnpm 11, enforces package engine checks, and applies a minimum package release age (#293)

Breaking Changes

Custom renderer bridges that implement the core executeAction callback must now accept an ActionBinding instead of a bare action name. This exposes chained action params to custom integrations at compile time (#307)

Contributors

@ctate

@Railly

@tmchow

@wotnak

New Features

Custom directives API — @json-render/core now supports custom directives via defineDirective, letting you declare new JSON shapes (like $format, $math) that resolve to computed values at render time. Directives compose naturally — nest $format over $math over $state and they resolve inside-out. All four renderers (React, Vue, Svelte, Solid) have built-in directive resolution (#279)

@json-render/directives — New package shipping seven ready-made directives: $format (date, currency, number, percent via Intl), $math (add, subtract, multiply, divide, mod, min, max, round, floor, ceil, abs), $concat, $count, $truncate, $pluralize, and $join. Also exports createI18nDirective for $t translation keys with {{param}} interpolation, and standardDirectives for one-line registration (#279)

Improvements

Example READMEs — Added documentation to the chat, dashboard, game-engine, and no-ai examples (#277)

Contributors

@ctate

New Features

Devtools — Five new packages for inspecting json-render apps in the browser: @json-render/devtools (framework-agnostic core), plus @json-render/devtools-react, @json-render/devtools-vue, @json-render/devtools-svelte, and @json-render/devtools-solid adapters. Drop <JsonRenderDevtools /> into your app to get a shadow-DOM-isolated panel with six tabs (Spec, State, Actions, Stream, Catalog, Pick), a DOM picker that maps clicked elements back to spec keys via data-jr-key, a capped event store, and server-side stream tap utilities. Floating toggle or Cmd/Ctrl + Shift + J, tree-shakes to null in production (#273)

Devtools example — New examples/devtools Next.js demo showing the full devtools panel wired up to an AI chat endpoint and a component catalog (#273)

Action observer and devtools flag in core — @json-render/core now exposes an action observer and a devtools enablement flag that adapters use to mirror actions and stream events into the panel (#273)

Bug Fixes

Zod 4 schema formatting — formatZodType now correctly handles z.record(), z.default(), and z.literal() types from Zod 4, which previously produced incorrect or empty output in generated prompts and schemas (#239)

Improvements

Zod 4 test coverage — Added unit tests for formatZodType covering record, default, and literal types to guard against regressions (#272)

Contributors

@ctate

@mvanhorn

New Features

• Gaussian Splatting — Added GaussianSplat component to @json-render/react-three-fiber, bringing the component count to 20. Composable with all existing R3F components (lights, controls, post-processing) via drei's Splat loader (#259)
• Standalone gsplat example — Experimental demo app showcasing Gaussian Splatting with gsplat.js (no Three.js dependency), featuring scene selector, live JSON spec viewer, and progress indicator (#259)
• R3F gsplat example — Demo app with five scenes: splat showroom, splat with primitives, multi-splat, post-processing effects, and animated floating splat (#259)

Improved

• AI output quality — Improved prompt output and schema generation for more reliable AI-generated specs (#268)

Contributors

• @ctate
• @willmanzoli

Minor Changes

519a538: Add Next.js renderer and shadcn-svelte component library.

New:

• @json-render/next -- Next.js renderer that turns JSON specs into full Next.js applications with routes, layouts, SSR, metadata, data loaders, and static generation. Client and server entry points at @json-render/next and @json-render/next/server. Includes built-in Link, Slot, error boundary, loading, and not-found components.
• @json-render/shadcn-svelte -- Pre-built shadcn-svelte components for json-render Svelte apps. 36 components built on Svelte 5 + Tailwind CSS with state binding, validation, and action support. Server-safe catalog at @json-render/shadcn-svelte/catalog.

Patch Changes

Updated dependencies [519a538]

• @json-render/[email protected]
• @json-render/[email protected]