@json-render/next
Next.js renderer that converts JSON specs into full Next.js applications with routes, pages, layouts, metadata, and SSR support.
Quick Start
npm install @json-render/core @json-render/react @json-render/next1. Define Your Spec
// lib/spec.ts
import type { NextAppSpec } from "@json-render/next";
export const spec: NextAppSpec = {
metadata: {
title: { default: "My App", template: "%s | My App" },
description: "A json-render Next.js application",
},
layouts: {
main: {
root: "shell",
elements: {
shell: { type: "Container", props: {}, children: ["nav", "slot"] },
nav: { type: "NavBar", props: { links: [
{ href: "/", label: "Home" },
{ href: "/about", label: "About" },
]}, children: [] },
slot: { type: "Slot", props: {}, children: [] },
},
},
},
routes: {
"/": {
layout: "main",
metadata: { title: "Home" },
page: {
root: "hero",
elements: {
hero: { type: "Card", props: { title: "Welcome" }, children: [] },
},
},
},
"/about": {
layout: "main",
metadata: { title: "About" },
page: {
root: "content",
elements: {
content: { type: "Card", props: { title: "About Us" }, children: [] },
},
},
},
},
};2. Create the App
// lib/app.ts
import { createNextApp } from "@json-render/next/server";
import { spec } from "./spec";
export const { Page, generateMetadata, generateStaticParams } = createNextApp({
spec,
loaders: {
// Server-side data loaders (optional)
loadPost: async ({ slug }) => {
const post = await getPost(slug as string);
return { post };
},
},
});3. Wire Up Route Files
// app/[[...slug]]/page.tsx
export { Page as default, generateMetadata, generateStaticParams } from "@/lib/app";// app/[[...slug]]/layout.tsx
import { NextAppProvider } from "@json-render/next";
import { registry, handlers } from "@/lib/registry";
export default function Layout({ children }: { children: React.ReactNode }) {
return (
<html lang="en">
<body>
<NextAppProvider registry={registry} handlers={handlers}>
{children}
</NextAppProvider>
</body>
</html>
);
}Key Concepts
NextAppSpec
The top-level spec defines an entire Next.js application:
- metadata: Root-level SEO metadata (title template, description, OpenGraph)
- layouts: Reusable layout element trees (each must include a
Slotcomponent) - routes: Route definitions keyed by URL pattern
- state: Global initial state shared across all routes
Route Patterns
Routes use Next.js URL conventions:
"/"-- home page"/about"-- static route"/blog/[slug]"-- dynamic segment"/docs/[...path]"-- catch-all segment"/settings/[[...path]]"-- optional catch-all segment
Layouts
Layouts wrap page content. Every layout MUST include a Slot component where page content will be rendered. Layouts are defined once in spec.layouts and referenced by routes via the layout field.
Built-in Components
- Slot: Placeholder in layouts where page content is rendered
- Link: Client-side navigation link (wraps
next/link)
Built-in Actions
- setState: Update state value. Params:
{statePath, value} - pushState: Append to array. Params:
{statePath, value, clearStatePath?} - removeState: Remove from array by index. Params:
{statePath, index} - navigate: Client-side navigation. Params:
{href}
Data Loaders
Server-side async functions that run in the Server Component before rendering. Results are merged into the page's initial state.
createNextApp({
spec,
loaders: {
loadPost: async ({ slug }) => {
const post = await db.post.findUnique({ where: { slug } });
return { post };
},
},
});SSR
Pages are server-rendered automatically. The createNextApp Page component is an async Server Component that:
- Matches the route from the spec
- Runs server-side data loaders
- Generates metadata
- Passes the resolved spec to the client renderer for hydration
Entry Points
@json-render/next-- Client components (NextAppProvider, PageRenderer, Link)@json-render/next/server-- Server utilities (createNextApp, matchRoute, schema)
API Reference
Server Exports (@json-render/next/server)
createNextApp(options)-- Create Page, generateMetadata, generateStaticParamsschema-- Custom schema for Next.js apps (for AI catalog generation)matchRoute(spec, pathname)-- Match a URL to a route specresolveMetadata(spec, route)-- Resolve metadata for a routeslugToPath(slug)-- Convert catch-all slug array to pathnamecollectStaticParams(spec)-- Collect static params for all routes
Client Exports (@json-render/next)
NextAppProvider-- Context provider for registry and handlersPageRenderer-- Renders a page spec with optional layoutNextErrorBoundary-- Error boundary componentNextLoading-- Loading state componentNextNotFound-- Not-found componentLink-- Built-in navigation component (wraps next/link)