@textui/core

The runtime: a reactive store, typed registries, a cell-diffing renderer, hooks, and the four host primitives. Everything else in TextUI sits on this.

npm install @textui/core

The one idea

JSX compiles to data. <Row gap={1}/> and { component: 'Row', gap: 1 } are the same value, and the runtime mounts either. A screen can be written in TypeScript, loaded from JSON, generated, edited or sent over a wire without the runtime changing.

import { h, renderToString } from '@textui/core';

console.log(renderToString(
  h('box', { margin: 1, border: 'single' }, h('text', { content: 'hello' })),
  { width: 30 },
));

Capitalized spellings of the primitives exist for JSX - Box, Text, Canvas are the strings themselves, so <Box/> and <box/> produce the identical node.

What is in here, and what is not

The four primitives - box, text, canvas, spacer - are here because the layout engine and the painter are the things that reason about them. The eighty-seven components built out of them are @textui/widgets, a separate package that depends on this one.

That split is not tidiness. An imported component travels on its own node, so a screen written in JSX resolves without a registry at all:

import { Badge } from '@textui/widgets';

renderToString(h(Badge, { label: 'ok' }), { width: 20 });  // registry empty

The registry is for the case JSX cannot cover - a component named by a string, in JSON, a template renderer, or an extension. render takes those through its components option.

The parts

| | | |---|---| | Store | One reactive tree addressed by path. A prop can be { path: '$/x' } and the runtime resolves it and redraws when it changes | | Registries | Components, commands, keybindings, themes, shells, surfaces, resources - typed, and disposable | | Renderer | Diffs cells rather than redrawing frames. renderOnce and renderToString draw one frame with no terminal at all | | Hooks | useState, useEffect, useStore, useFocus, useInterval and thirty more - module imports, not a second argument | | Layers | Dialogs, palettes, toasts and tooltips are entries on five planes, so focus trapping and dismissal are decided once |

Runtime

No dependencies, and no node: imports - this package never touches a filesystem or a process. It runs on Node 22+ and on Bun, and would run in a browser against a virtual terminal.

Documentation

https://softov.github.io/textui/

Part of TextUI - documentation - getting started

@textui/kit one install · @textui/core the runtime · @textui/widgets the catalog · @textui/terminal adapters and input · @textui/testing the harness · @textui/cli the CLI