Rezi

Rezi is a code-first terminal UI framework for Node.js and Bun. It uses a declarative widget API, deterministic input routing, and native-backed rendering through the Zireael C engine.

Status: pre-alpha. Rezi is under active development. Public APIs, ABI details, and behavior may change between releases. It is not yet recommended for production workloads.

Focus

• ui.* widget factories as the canonical API
• deterministic rendering and event routing
• native-backed layout and framebuffer diffing
• explicit focus, forms, routing, and theme control
• optional JSX support through @rezi-ui/jsx

Architecture

Getting Started

Public Templates

• minimal - single-screen utility starter
• cli-tool - routed multi-screen workflow starter
• starship - advanced console starter with tabs, charts, overlays, and broad widget coverage

Example Surfaces

• Repository examples: examples/hello-counter, examples/raw-draw-demo, examples/gallery
• Validation app: examples/regression-dashboard

Core Concepts

State-Driven Rendering

Rezi applications are state-driven. You define a view function that returns a widget tree based on application state:

type State = { items: string[]; selected: number };

app.view((state) =>
  ui.column({ gap: 1 },
    state.items.map((item, i) =>
      ui.text(i === state.selected ? `> ${item}` : `  ${item}`, {
        key: String(i),
      })
    )
  )
);

State Updates

Update state with app.update(). Updates are batched and coalesced for efficiency:

app.update((prev) => ({ ...prev, selected: prev.selected + 1 }));