ratatui-ts — TypeScript Terminal UI (TUI) powered by Rust Ratatui

High‑performance, cross‑platform Terminal UI (TUI) for TypeScript/Node.js. ratatui-ts exposes the battle‑tested Rust Ratatui engine over a stable C ABI with idiomatic TS helpers for widgets, layout, batched frames, and headless snapshot rendering. Works on Linux, macOS, and Windows.

Highlights

• Rich widgets: Paragraph, List (stateful), Table (stateful), Gauge, Tabs, BarChart, Sparkline, Chart, Scrollbar (feature‑gated), Canvas, LineGauge.
• Events: keyboard and mouse (down/up/drag/move/scroll + modifiers), resize.
• Rendering: draw into rects; batched drawFrame for multiple widgets.
• Testing: headless renderers for widgets and composite frames; styles_ex and structured cell dumps.
• Ergonomics: builders for spans/lines/rows, layout helpers, FrameBuilder, color helpers.
• Coverage: 100% FFI parity guard via introspector JSON.

Why ratatui‑ts?

• Performance first: rendering, layout, and input run in native Rust; the TS layer is thin and predictable.
• Production‑grade testing: headless text, style, and cell snapshots keep UIs stable across refactors.
• Developer‑friendly: typed enums, builder helpers, and batched frame APIs reduce ceremony and round‑trips.
• Stability: explicit, flat C ABI; a coverage checker guarantees evolution without drift.

Install

1. Build the Rust cdylib first:

cargo build --release -p ratatui_ffi

This produces a platform-specific dynamic library in ratatui-ffi/target/release/:

• Linux: libratatui_ffi.so
• macOS: libratatui_ffi.dylib
• Windows: ratatui_ffi.dll

2. Install from npm (bindings only):

npm install ratatui-ts

If your library is not in the default search location, set:

• RATATUI_FFI_PATH to the absolute path of the compiled library file

Notes on Node versions, ffi-napi, and CI

• Native layer choice: These bindings use ffi-napi/ref-napi. They are widely used but can be sensitive to Node.js header/ABI shifts and node-gyp toolchains in clean CI environments.
• Prebuilts first: We ship prebuilt ratatui_ffi libraries in prebuilt/<platform-arch>/ and prefer loading them at runtime. You can also point to a locally built ratatui_ffi via RATATUI_FFI_PATH.
• CI publish environment: Our GitHub Actions publish job currently uses Node 18 to avoid transient ffi-napi build breakage on newer Node releases when npm attempts to build from source.
• Local dev guidance: Node 18–20 are recommended. On bleeding‑edge Node (e.g., 24.x), if ffi-napi rebuilds and fails, use an LTS Node (18/20) via nvm, or skip rebuilding entirely by using the shipped prebuilts with RATATUI_FFI_PATH.
• Why you might see node-gyp errors: Some ecosystems deps (e.g., get-uv-event-loop-napi-h, node-addon-api) periodically tighten types or change headers; this can surface as C++ signature/const‑qualification errors when rebuilding ffi-napi. These do not affect the correctness of Ratatui itself; they’re build‑time friction when a rebuild is attempted.

Examples

• Full scene (layout + chart + canvas): examples/full-scene.ts
• Batch widgets (paragraph/list/tabs/table/chart/bar/spark): examples/batch-widgets.ts
• Minimal terminal loop: examples/terminal-loop.ts

See more in docs/EXAMPLES.md.

Demo via npx

You can also try the interactive demo directly once published:

npx -y ratatui-ts-demos

Note on Node versions: This demo uses a native addon layer (ffi-napi). On bleeding‑edge Node.js (e.g., 24.x), npx may fail if the addon hasn’t released a compatible build yet. That’s not your app — it’s the system Node vs. native addon mismatch. For a quick try, use an LTS Node (18/20) or run with a project‑local Node version. Prefer a different vibe? The Python and C# bindings offer equally polished demos and headless tests:

• Python: https://github.com/holo-q/ratatui-py
• .NET/C#: https://github.com/holo-q/Ratatui.cs

Snapshots

These are generated by CI from our headless renderers after a green build. They provide a quick visual seal that widgets render correctly end‑to‑end.

Paragraph	Table
Chart	Combined

Usage

import {
  Terminal, Paragraph, List, Table, Gauge, Tabs, BarChart, Sparkline, Chart,
  color, styleMods, key, eventKind, mouseKind, mouseButton, widgetKind, rect,
  headlessRender, headlessRenderFrame,
} from 'ratatui-ts';

// Terminal lifecycle
const term = Terminal.init();
try {
  // Draw a Paragraph full-screen
  const p = Paragraph.fromText('Hello from ratatui!');
  p.setBlockTitle('Demo', true);
  term.drawParagraph(p);

  // Poll events (500ms timeout)
const evt = Terminal.nextEvent(500);
if (evt && evt.kind === eventKind.Key) {
  if (evt.key.code === key.Enter) {
    console.log('Enter pressed');
  }
}
} finally {
  term.free(); // restore terminal state
}

// Headless rendering (for tests/CI)
const p2 = Paragraph.fromText('Boxed text');
// show borders and a title
p2.setBlockTitle('Box', true);
const out = headlessRender(20, 3, p2);
console.log(out);

Platform loading

• By default the loader tries:
  • RATATUI_FFI_PATH (if set)
  • ../ratatui-ffi/target/release/<libname> relative to this package
  • ../../ratatui-ffi/target/release/<libname> as a fallback

You can also explicitly pass a path to loadLibrary(path).

Features

• Full widget surface: Paragraph, List (stateful), Table (stateful), Gauge, Tabs, BarChart, Sparkline, Chart, Scrollbar (feature‑gated), Canvas, LineGauge.
• Batched frames: drawFrame(term, cmds) and headlessRenderFrame(w,h,cmds).
• Builders: buildSpans/LineSpans/CellsLines/RowsCellsLines to batch inputs efficiently.
• Layout: layoutSplitEx2 and layoutSplitPercentages helpers.
• Headless: per‑widget helpers plus styles_ex and structured cells for precise snapshots.
• Version/feature: getVersion() and getFeatureBits(); color helpers: colorHelper.rgb/idx.

Platform support

• Linux: x64 tested; aarch64 supported via native build or prebuilts.
• macOS: Apple Silicon and Intel via dylib.
• Windows: ratatui_ffi.dll.

TypeScript niceties

• Batch builders for spans/lines/rows to minimize FFI calls.
• Layout helpers (layoutSplitEx2, layoutSplitPercentages) and FrameBuilder for batched drawing.
• Headless helpers for full frames: text, styles_ex, and structured cells.
• Rich widget APIs (blockAdv, title alignment, batch setters) while staying 1:1 with FFI.
• Version and feature bits (getVersion(), getFeatureBits()), color helpers (colorHelper.rgb/idx).

See the full feature guide: docs/TS-FEATURES.md. For the broader quality roadmap: docs/QUALITY-ROADMAP.md.

Coverage check (bindings ↔ FFI)

• Generate introspection JSON from the Rust side:

cd ratatui-ffi && cargo run --quiet --bin ffi_introspect -- --json > /tmp/ffi.json

• Run the TS coverage checker (fails on missing bindings):

node scripts/check-introspection.js /tmp/ffi.json --features-map scripts/features-map.json

• Optional: gate by feature bits (requires ffi-napi installed in this repo and a compiled library path):

node scripts/check-introspection.js /tmp/ffi.json --lib ./ratatui-ffi/target/release/libratatui_ffi.so --features-map scripts/features-map.json

• Use --allow path/to/allow.txt to temporarily silence known gaps (one export name per line). The script exits non-zero on any missing or invalid declarations.

API surface

• Classes
  • Terminal: init(), clear(), size(), per-widget drawXxxIn(), free(), static nextEvent(timeout) returns a typed union (Event).
  • Paragraph: fromText(), setBlockTitle(), appendLine(), free().
  • List, Table, Gauge, Tabs, BarChart, Sparkline, Chart, Scrollbar (optional): predictable set... and free() methods + handle property for batching.
  • Batched: makeDrawCmd(kind, handle, rect), drawFrame(term, cmds).
• Headless helpers
  • headlessRender(width, height, paragraph)
  • headlessRenderFrame(width, height, cmds)
  • headlessRenderXxx(...) for most widgets
• Enums
  • Colors: color.*
  • Styles: styleMods.*
  • Keys: key.* (includes F1..F12 via numeric codes)
  • Events: eventKind.*; typed union Event for convenience
  • Mouse: mouseKind.*, mouseButton.*
  • Widgets: widgetKind.*

Comparisons

• Blessed/Ink: great for Node.js text UIs. ratatui-ts targets high‑performance, retained‑mode widgets with robust layout, composable frames, and deterministic headless testing.
• ncurses wrappers: low‑level control; ratatui-ts provides modern widgets, layout primitives, and snapshot‑friendly rendering.

ESM and CJS

• Dual build is provided. Use either:
  • ESM: import { Terminal } from 'ratatui-ts' (resolves to dist/esm/index.js)
  • CJS: const { Terminal } = require('ratatui-ts') (resolves to dist/cjs/index.js)

BigInt-safe 64-bit values

• For BarChart.setValues() and Sparkline.setValues(), you may pass bigint[] or number[].
• Values are marshalled as true unsigned 64-bit (little-endian) to avoid precision loss.

Testing (headless)

• Snapshot‑style tests can use headless helpers to render into strings without a TTY.
• Example (Vitest): see test/paragraph.spec.ts.
• Tests auto‑skip if the native library is not found. Set RATATUI_FFI_PATH to enable execution on CI.

Resource management

• Short‑lived scripts: GC finalizers free native objects automatically.
• Long‑running apps and hot loops: call .free() when done with widgets; always free Terminal in a finally block to restore raw/alt/cursor.
• Builders (buildSpans/LineSpans/...) do not require manual free; they keep inputs alive only for the duration of the call.

See docs/RESOURCE-MANAGEMENT.md for guidance and examples.

Postinstall check

• postinstall will check for the native library in common locations and warn if not found. It does not build the Rust code for you.
• Build the Rust side separately, or ship prebuilt binaries for your target platforms.

Packaging prebuilt libraries (optional)

• If you plan to publish to npm with prebuilt native libraries, consider:
  • Adding release assets from your CI (e.g., GitHub Actions) covering Linux/macOS/Windows and architectures.
  • A postinstall script that downloads the right asset if RATATUI_FFI_PATH is not set, with checksum verification.
  • Keep the dynamic library outside your JS bundle; point the loader to it via RATATUI_FFI_PATH.

Node-API addon (optional)

• For maximum performance and fewer allocations, a Node-API (napi-rs) addon can wrap the same Rust logic.
• This repo focuses on C ABI + ffi-napi for portability and simplicity. If you want the addon path, we can scaffold a separate crate and @ratatui/ts-napi package.

Bindings family

• Python: https://github.com/holo-q/ratatui-py — typed Python bindings with docs site, demos, and utilities for responsive apps.
• .NET/C#: https://github.com/holo-q/Ratatui.cs — high‑performance C# API with headless snapshots and per‑RID prebuilts.