@json-render/ink

Ink terminal renderer that converts JSON specs into interactive terminal component trees with standard components, data binding, visibility, actions, and dynamic props.

Quick Start

import { defineCatalog } from "@json-render/core";
import { schema } from "@json-render/ink/schema";
import {
  standardComponentDefinitions,
  standardActionDefinitions,
} from "@json-render/ink/catalog";
import { defineRegistry, Renderer, type Components } from "@json-render/ink";
import { z } from "zod";

// Create catalog with standard + custom components
const catalog = defineCatalog(schema, {
  components: {
    ...standardComponentDefinitions,
    CustomWidget: {
      props: z.object({ title: z.string() }),
      slots: [],
      description: "Custom widget",
    },
  },
  actions: standardActionDefinitions,
});

// Register only custom components (standard ones are built-in)
const { registry } = defineRegistry(catalog, {
  components: {
    CustomWidget: ({ props }) => <Text>{props.title}</Text>,
  } as Components<typeof catalog>,
});

// Render
function App({ spec }) {
  return (
    <JSONUIProvider initialState={{}}>
      <Renderer spec={spec} registry={registry} />
    </JSONUIProvider>
  );
}

Spec Structure (Flat Element Map)

The Ink schema uses a flat element map with a root key:

{
  "root": "main",
  "elements": {
    "main": {
      "type": "Box",
      "props": { "flexDirection": "column", "padding": 1 },
      "children": ["heading", "content"]
    },
    "heading": {
      "type": "Heading",
      "props": { "text": "Dashboard", "level": "h1" },
      "children": []
    },
    "content": {
      "type": "Text",
      "props": { "text": "Hello from the terminal!" },
      "children": []
    }
  }
}

Standard Components

Layout

• Box - Flexbox layout container (like a terminal <div>). Use for grouping, spacing, borders, alignment. Default flexDirection is row.
• Text - Text output with optional styling (color, bold, italic, etc.)
• Newline - Inserts blank lines. Must be inside a Box with flexDirection column.
• Spacer - Flexible empty space that expands along the main axis.

Content

• Heading - Section heading (h1: bold+underlined, h2: bold, h3: bold+dimmed, h4: dimmed)
• Divider - Horizontal separator with optional centered title
• Badge - Colored inline label (variants: default, info, success, warning, error)
• Spinner - Animated loading spinner with optional label
• ProgressBar - Horizontal progress bar (0-1)
• Sparkline - Inline chart using Unicode block characters
• BarChart - Horizontal bar chart with labels and values
• Table - Tabular data with headers and rows
• List - Bulleted or numbered list
• ListItem - Structured list row with title, subtitle, leading/trailing text
• Card - Bordered container with optional title
• KeyValue - Key-value pair display
• Link - Clickable URL with optional label
• StatusLine - Status message with colored icon (info, success, warning, error)
• Markdown - Renders markdown text with terminal styling

Interactive

• TextInput - Text input field (events: submit, change)
• Select - Selection menu with arrow key navigation (events: change)
• MultiSelect - Multi-selection with space to toggle (events: change, submit)
• ConfirmInput - Yes/No confirmation prompt (events: confirm, deny)
• Tabs - Tab bar navigation with left/right arrow keys (events: change)

Visibility Conditions

Use visible on elements to show/hide based on state. Syntax: { "$state": "/path" }, { "$state": "/path", "eq": value }, { "$state": "/path", "not": true }, { "$and": [cond1, cond2] } for AND, { "$or": [cond1, cond2] } for OR.

Dynamic Prop Expressions

Any prop value can be a data-driven expression resolved at render time:

• { "$state": "/state/key" } - reads from state model (one-way read)
• { "$bindState": "/path" } - two-way binding: use on the natural value prop of form components
• { "$bindItem": "field" } - two-way binding to a repeat item field
• { "$cond": <condition>, "$then": <value>, "$else": <value> } - conditional value
• { "$template": "Hello, ${/name}!" } - interpolates state values into strings

Components do not use a statePath prop for two-way binding. Use { "$bindState": "/path" } on the natural value prop instead.

Event System

Components use emit to fire named events. The element's on field maps events to action bindings:

CustomButton: ({ props, emit }) => (
  <Box>
    <Text>{props.label}</Text>
    {/* emit("press") triggers the action bound in the spec's on.press */}
  </Box>
),

{
  "type": "CustomButton",
  "props": { "label": "Submit" },
  "on": { "press": { "action": "submit" } },
  "children": []
}

Built-in Actions

setState, pushState, and removeState are built-in and handled automatically:

{ "action": "setState", "params": { "statePath": "/activeTab", "value": "home" } }
{ "action": "pushState", "params": { "statePath": "/items", "value": { "text": "New" } } }
{ "action": "removeState", "params": { "statePath": "/items", "index": 0 } }

Repeat (Dynamic Lists)

Use the repeat field on a container element to render items from a state array:

{
  "type": "Box",
  "props": { "flexDirection": "column" },
  "repeat": { "statePath": "/items", "key": "id" },
  "children": ["item-row"]
}

Inside repeated children, use { "$item": "field" } to read from the current item and { "$index": true } for the current index.

For nested lists, an inner repeat can use { "statePath": { "$item": "children" } } to iterate an array on the enclosing item.

Streaming

Use useUIStream to progressively render specs from JSONL patch streams:

import { useUIStream } from "@json-render/ink";

const { spec, send, isStreaming } = useUIStream({ api: "/api/generate" });

Server-Side Prompt Generation

Use the ./server export to generate AI system prompts from your catalog:

import { catalog } from "./catalog";

const systemPrompt = catalog.prompt({ system: "You are a terminal assistant." });

Providers

Provider	Purpose
StateProvider	Share state across components (JSON Pointer paths). Accepts optional store prop for controlled mode.
ActionProvider	Handle actions dispatched via the event system
VisibilityProvider	Enable conditional rendering based on state
ValidationProvider	Form field validation
FocusProvider	Manage focus across interactive components
JSONUIProvider	Combined provider for all contexts

External Store (Controlled Mode)

Pass a StateStore to StateProvider (or JSONUIProvider) to use external state management:

import { createStateStore, type StateStore } from "@json-render/ink";

const store = createStateStore({ count: 0 });

<StateProvider store={store}>{children}</StateProvider>

store.set("/count", 1); // React re-renders automatically

When store is provided, initialState and onStateChange are ignored.

createRenderer (Higher-Level API)

import { createRenderer } from "@json-render/ink";
import { standardComponents } from "@json-render/ink";
import { catalog } from "./catalog";

const InkRenderer = createRenderer(catalog, {
  ...standardComponents,
  // custom component overrides here
});

// InkRenderer includes all providers (state, visibility, actions, focus)
render(
  <InkRenderer spec={spec} state={{ activeTab: "overview" }} />
);

Key Exports

Export	Purpose
defineRegistry	Create a type-safe component registry from a catalog
Renderer	Render a spec using a registry
createRenderer	Higher-level: creates a component with built-in providers
JSONUIProvider	Combined provider for all contexts
schema	Ink flat element map schema (includes built-in state actions)
standardComponentDefinitions	Catalog definitions for all standard components
standardActionDefinitions	Catalog definitions for standard actions
standardComponents	Pre-built component implementations
useStateStore	Access state context
useStateValue	Get single value from state
useBoundProp	Two-way binding for $bindState/$bindItem expressions
useActions	Access actions context
useAction	Get a single action dispatch function
useOptionalValidation	Non-throwing variant of useValidation
useUIStream	Stream specs from an API endpoint
createStateStore	Create a framework-agnostic in-memory StateStore
StateStore	Interface for plugging in external state management
Components	Typed component map (catalog-aware)
Actions	Typed action map (catalog-aware)
ComponentContext	Typed component context (catalog-aware)
flatToTree	Convert flat element map to tree structure

Terminal UI Design Guidelines

• Use Box for layout (flexDirection, padding, gap). Default flexDirection is row.
• Terminal width is ~80-120 columns. Prefer vertical layouts (flexDirection: column) for main structure.
• Use borderStyle on Box for visual grouping (single, double, round, bold).
• Use named terminal colors: red, green, yellow, blue, magenta, cyan, white, gray.
• Use Heading for section titles, Divider to separate sections, Badge for status, KeyValue for labeled data, Card for bordered groups.
• Use Tabs for multi-view UIs with visible conditions on child content.
• Use Sparkline for inline trends and BarChart for comparing values.