@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.

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

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

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.