json-render

@json-render/svelte

Svelte 5 components, providers, and helpers for rendering json-render specs.

Installation

npm install @json-render/core @json-render/svelte

Peer dependencies: svelte ^5.0.0 and zod ^4.0.0.

npm install svelte zod

Components

Renderer

<Renderer
  spec={spec}       // Spec | null
  registry={registry}
  loading={false}
/>

Renders a spec with your component registry. If spec is null, it renders nothing.

JsonUIProvider

Convenience wrapper around StateProvider, VisibilityProvider, ValidationProvider, and ActionProvider.

<JsonUIProvider
  initialState={{}}
  handlers={handlers}
  validationFunctions={validationFunctions}
>
  <Renderer {spec} {registry} />
</JsonUIProvider>

defineRegistry

Create a typed component registry and action handlers from a catalog.

import { defineRegistry } from "@json-render/svelte";

const { registry, handlers, executeAction } = defineRegistry(catalog, {
  components: {
    Card,
    Button,
  },
  actions: {
    submit: async (params, setState, state) => {
      // custom action logic
    },
  },
});

handlers is designed for JsonUIProvider/ActionProvider. executeAction is an imperative helper.

Component Props

Registry components receive BaseComponentProps<TProps>:

interface BaseComponentProps<TProps> {
  props: TProps;
  children?: Snippet;
  emit: (event: string) => void;
  bindings?: Record<string, string>;
  loading?: boolean;
}

Use emit("eventName") to trigger handlers declared in the spec on bindings.

Context Helpers

Use these helpers inside Svelte components:

  • getStateValue(path) - read/write state via .current
  • getBoundProp(() => value, () => bindingPath) - write back resolved $bindState / $bindItem values
  • isVisible(condition) - evaluate visibility via .current
  • getAction(name) - read a registered action handler via .current
  • getFieldValidation(ctx, path, config) - get field validation state + actions

For advanced usage, access full contexts:

  • getStateContext()
  • getActionContext()
  • getVisibilityContext()
  • getValidationContext()
  • getOptionalValidationContext()

Streaming

createUIStream

const stream = createUIStream({
  api: "/api/generate-ui",
  onComplete: (spec) => console.log(spec),
});

await stream.send("Create a login form");

console.log(stream.spec);
console.log(stream.isStreaming);

createChatUI

const chat = createChatUI({ api: "/api/chat-ui" });
await chat.send("Build a settings panel");
console.log(chat.messages, chat.isStreaming);

Schema Export

Use schema from @json-render/svelte when defining catalogs for Svelte specs.