$ show vadimdemedes/ink
Ink is a mature, widely-adopted React renderer for building terminal/CLI applications — 'React for CLIs.' It implements a custom react-reconciler host config (src/reconciler.ts) that maps React elements to a lightweight virtual DOM (src/dom.ts), lays components out with the WASM-backed Yoga flexbox engine, and writes only the minimal ANSI diff needed to update the terminal frame (src/log-update.ts, src/line-update.ts). Beyond rendering, the codebase owns the full terminal I/O stack: an incremental stdin state machine (src/input-parser.ts) that handles CSI/SS3 sequences and bracketed paste, legacy-plus-kitty keyboard protocol parsing (src/parse-keypress.ts), ANSI tokenizing/sanitizing (src/ansi-tokenizer.ts, src/sanitize-ansi.ts), wide-character-safe clipping (src/output.ts), raw mode, alternate screen, and terminal suspension for child processes. Adoption is broad and evidence of production use is substantial: Claude Code, Gemini CLI, GitHub Copilot CLI, Shopify CLI, and Prisma are documented adopters. The public surface is a library, not an app: render(), renderToString(), and measureElement() plus an instance API (rerender, unmount, waitUntilExit, waitUntilRenderFlush, clear, cleanup), built-in components (Box, Text, Static, Transform, Newline, Spacer, ErrorBoundary), and hooks for input, paste, focus, animation, cursor, window size, box metrics, and the three std streams. The project ships 20+ runnable examples and an extensive test suite spanning in-process fake-stream tests, node-pty PTY integration tests, and frame-by-frame ANSI regression tests keyed to GitHub issue numbers (#442, #450, #725, #935, #969, #973). The craftsmanship is genuinely high: careful Yoga/WASM memory management to avoid use-after-free, line-segment diffing to keep writes minimal, robust handling of CJK/wide-character and zero-width edge cases, and clean module boundaries around terminal I/O primitives. Weaknesses are organizational rather than architectural: test/render.tsx is a monolithic ~44k-token file, App.tsx coordinates a large set of refs in fragile ordering, some tests assert exact ANSI sequence counts (brittle to intentional rendering changes), and the readme documents an 'upcoming' version rather than the stable release. Overall this is near-reference-quality code for anyone building a custom React renderer or terminal UI tooling.
The LLM identified 7 files worth highlighting for reuse:
Custom React host configuration that maps React elements to terminal DOM nodes (ink-root, ink-box, ink-text) and drives Yoga flexbox layout. Handles static node tracking, Suspense, transitions, error callbacks, and WASM Yoga memory cleanup. This is the canonical reference architecture for building a custom React renderer — any engineer implementing a non-DOM React target should study this host config.
Incremental parser for stdin chunks that recognizes CSI/SS3 control sequences and bracketed paste while buffering partial sequences across chunk boundaries, with flush/reset semantics. Self-contained state machine directly extractable into any terminal input library, TUI framework, or CLI framework needing robust raw-mode input handling.
Tokenizes terminal output into plain text, ANSI color sequences, and control strings, preserving SGR styling and hyperlinks. A standalone reusable primitive for parsing, sanitizing, or post-processing ANSI output — could power log colorizers, terminal emulator tooling, or test assertion helpers with minimal adaptation.
Virtual terminal buffer that applies write and clip operations with wide-character boundary cleanup and nested clip intersection. Solves the hard Unicode composition edge cases (CJK wide chars, zero-width codes) of writing text into a fixed-size terminal region. Extractable pattern for terminal compositors, editors, and pane-based UIs.
Frame renderer supporting standard and incremental modes: tracks cursor position, rewrites only changed line segments, and wraps output in synchronized-update (BSU/ESU) sequences to eliminate flicker. Demonstrates a robust strategy for minimizing terminal writes in real-time dashboards, progress displays, and live-updating CLIs; the diffing approach is reusable in any terminal output layer.
Text wrapping and truncation with caching, handling ANSI sequences and wide characters correctly. Self-contained text-layout utility that could be extracted into any terminal-oriented project needing Unicode-aware word wrap without corrupting escape codes.
PTY-based terminal integration harness that spawns a real pseudo-terminal, strips transport sequences (BSU/ESU), supports waitForOutput, write, and resize, and reconstructs the visible terminal buffer from raw ANSI output. An adaptable black-box testing pattern for any interactive CLI application that needs to assert real terminal behavior rather than mocked streams.