ink README

The project's README from github.com/vadimdemedes/ink. As one markdown file: README.md.



Ink


React for CLIs. Build and test your CLI output using components.

Build Status npm

Ink provides the same component-based UI building experience that React offers in the browser, but for command-line apps. It uses Yoga to build Flexbox layouts in the terminal, so most CSS-like properties are available in Ink as well. If you are already familiar with React, you already know Ink.

Since Ink is a React renderer, all features of React are supported. Head over to the React website for documentation on how to use it. Only Ink's methods are documented in this readme.

Fully AI-generated pull requests are not accepted. You can use AI, but should be verified and cleaned up by a human. Only Opus 4.6+ (high-effort) and Codex 5.4+ (extra high) are accepted models. Preferably created with Opus and verified by Codex.

My open source work is supported by the community ❤️

Install

npm install ink react

[!NOTE] This readme documents the upcoming version of Ink. For the latest stable release, see Ink on npm.

Usage

import React, {useState, useEffect} from 'react';
import {render, Text} from 'ink';

const Counter = () => {
	const [counter, setCounter] = useState(0);

	useEffect(() => {
		const timer = setInterval(() => {
			setCounter(previousCounter => previousCounter + 1);
		}, 100);

		return () => {
			clearInterval(timer);
		};
	}, []);

	return <Text color="green">{counter} tests passed</Text>;
};

render(<Counter />);

Who's Using Ink?

(PRs welcome. Append new entries at the end. Repos must have 100+ stars and showcase Ink beyond a basic list picker.)

Contents

Getting Started

Use create-ink-app to quickly scaffold a new Ink-based CLI.

npx create-ink-app my-ink-cli

Alternatively, create a TypeScript project:

npx create-ink-app --typescript my-ink-cli
Manual JavaScript setup

Ink requires the same Babel setup as you would do for regular React-based apps in the browser.

Set up Babel with a React preset to ensure all examples in this readme work as expected. After installing Babel, install @babel/preset-react and insert the following configuration in babel.config.json:

npm install --save-dev @babel/preset-react

{
	"presets": ["@babel/preset-react"]
}

Next, create a file source.js, where you'll type code that uses Ink:

import React from 'react';
import {render, Text} from 'ink';

const Demo = () => <Text>Hello World</Text>;

render(<Demo />);

Then, transpile this file with Babel:

npx babel source.js -o cli.js

Now you can run cli.js with Node.js:

node cli

If you don't like transpiling files during development, you can use import-jsx or @esbuild-kit/esm-loader to import a JSX file and transpile it on the fly.

Ink uses Yoga, a Flexbox layout engine, to build great user interfaces for your CLIs using familiar CSS-like properties you've used when building apps for the browser. It's important to remember that each element is a Flexbox container. Think of it as if every <div> in the browser had display: flex. See <Box> built-in component below for documentation on how to use Flexbox layouts in Ink. Note that all text must be wrapped in a <Text> component.

App Lifecycle

An Ink app is a Node.js process, so it stays alive only while there is active work in the event loop (timers, pending promises, useInput listening on stdin, etc.). If your component tree has no async work, the app will render once and exit immediately.

To exit the app, press Ctrl+C (enabled by default via exitOnCtrlC), call exit() from useApp inside a component, or call unmount() on the object returned by render().

Use waitUntilExit() to run code after the app is unmounted:

const {waitUntilExit} = render(<MyApp />);

await waitUntilExit();

console.log('App exited');

Components

<Text>

This component can display text and change its style to make it bold, underlined, italic, or strikethrough.

import {render, Text} from 'ink';

const Example = () => (
	<>
		<Text color="green">I am green</Text>
		<Text color="black" backgroundColor="white">
			I am black on white
		</Text>
		<Text color="#ffffff">I am white</Text>
		<Text bold>I am bold</Text>
		<Text italic>I am italic</Text>
		<Text underline>I am underline</Text>
		<Text strikethrough>I am strikethrough</Text>
		<Text inverse>I am inversed</Text>
	</>
);

render(<Example />);

[!NOTE] <Text> allows only text nodes and nested <Text> components inside of it. For example, <Box> component can't be used inside <Text>.

color

Type: string

Change text color. Ink uses chalk under the hood, so all its functionality is supported.

<Text color="green">Green</Text>
<Text color="#005cc5">Blue</Text>
<Text color="rgb(232, 131, 136)">Red</Text>

backgroundColor

Type: string

Same as color above, but for background.

<Text backgroundColor="green" color="white">Green</Text>
<Text backgroundColor="#005cc5" color="white">Blue</Text>
<Text backgroundColor="rgb(232, 131, 136)" color="white">Red</Text>

dimColor

Type: boolean
Default: false

Dim the color (make it less bright).

<Text color="red" dimColor>
	Dimmed Red
</Text>

bold

Type: boolean
Default: false

Make the text bold.

italic

Type: boolean
Default: false

Make the text italic.

underline

Type: boolean
Default: false

Make the text underlined.

strikethrough

Type: boolean
Default: false

Make the text crossed with a line.

inverse

Type: boolean
Default: false

Invert background and foreground colors.

<Text inverse color="yellow">
	Inversed Yellow
</Text>

wrap

Type: string
Allowed values: wrap hard truncate truncate-start truncate-middle truncate-end
Default: wrap

This property tells Ink to wrap or truncate text if its width is larger than the container. If wrap is passed (the default), Ink will wrap text and split it into multiple lines. If hard is passed, Ink will fill each line to the full column width, breaking words as necessary. If truncate-* is passed, Ink will truncate text instead, resulting in one line of text with the rest cut off.

<Box width={7}>
	<Text>Hello World</Text>
</Box>
//=> 'Hello\nWorld'

<Box width={7}>
	<Text wrap="hard">Hello World</Text>
</Box>
//=> 'Hello W\norld'

// `truncate` is an alias to `truncate-end`
<Box width={7}>
	<Text wrap="truncate">Hello World</Text>
</Box>
//=> 'Hello…'

<Box width={7}>
	<Text wrap="truncate-middle">Hello World</Text>
</Box>
//=> 'He…ld'

<Box width={7}>
	<Text wrap="truncate-start">Hello World</Text>
</Box>
//=> '…World'

<Box>

<Box> is an essential Ink component to build your layout. It's like <div style="display: flex"> in the browser.

import {render, Box, Text} from 'ink';

const Example = () => (
	<Box margin={2}>
		<Text>This is a box with margin</Text>
	</Box>
);

render(<Example />);

Dimensions

width

Type: number string

Width of the element in spaces. You can also set it as a percentage, which will calculate the width based on the width of the parent element.

<Box width={4}>
	<Text>X</Text>
</Box>
//=> 'X   '

<Box width={10}>
	<Box width="50%">
		<Text>X</Text>
	</Box>
	<Text>Y</Text>
</Box>
//=> 'X    Y'
height

Type: number string

Height of the element in lines (rows). You can also set it as a percentage, which will calculate the height based on the height of the parent element.

<Box height={4}>
	<Text>X</Text>
</Box>
//=> 'X\n\n\n'

<Box height={6} flexDirection="column">
	<Box height="50%">
		<Text>X</Text>
	</Box>
	<Text>Y</Text>
</Box>
//=> 'X\n\n\nY\n\n'
minWidth

Type: number

Sets a minimum width of the element. Percentages aren't supported yet; see https://github.com/facebook/yoga/issues/872.

minHeight

Type: number string

Sets a minimum height of the element in lines (rows). You can also set it as a percentage, which will calculate the minimum height based on the height of the parent element.

maxWidth

Type: number

Sets a maximum width of the element. Percentages aren't supported yet; see https://github.com/facebook/yoga/issues/872.

maxHeight

Type: number string

Sets a maximum height of the element in lines (rows). You can also set it as a percentage, which will calculate the maximum height based on the height of the parent element.

aspectRatio

Type: number

Defines the aspect ratio (width/height) for the element.

Use it with at least one size constraint (width, height, minHeight, or maxHeight) so Ink can derive the missing dimension.

Padding

paddingTop

Type: number
Default: 0

Top padding.

paddingBottom

Type: number
Default: 0

Bottom padding.

paddingLeft

Type: number
Default: 0

Left padding.

paddingRight

Type: number
Default: 0

Right padding.

paddingX

Type: number
Default: 0

Horizontal padding. Equivalent to setting paddingLeft and paddingRight.

paddingY

Type: number
Default: 0

Vertical padding. Equivalent to setting paddingTop and paddingBottom.

padding

Type: number
Default: 0

Padding on all sides. Equivalent to setting paddingTop, paddingBottom, paddingLeft and paddingRight.

<Box paddingTop={2}><Text>Top</Text></Box>
<Box paddingBottom={2}><Text>Bottom</Text></Box>
<Box paddingLeft={2}><Text>Left</Text></Box>
<Box paddingRight={2}><Text>Right</Text></Box>
<Box paddingX={2}><Text>Left and right</Text></Box>
<Box paddingY={2}><Text>Top and bottom</Text></Box>
<Box padding={2}><Text>Top, bottom, left and right</Text></Box>

Margin

marginTop

Type: number
Default: 0

Top margin.

marginBottom

Type: number
Default: 0

Bottom margin.

marginLeft

Type: number
Default: 0

Left margin.

marginRight

Type: number
Default: 0

Right margin.

marginX

Type: number
Default: 0

Horizontal margin. Equivalent to setting marginLeft and marginRight.

marginY

Type: number
Default: 0

Vertical margin. Equivalent to setting marginTop and marginBottom.

margin

Type: number
Default: 0

Margin on all sides. Equivalent to setting marginTop, marginBottom, marginLeft and marginRight.

<Box marginTop={2}><Text>Top</Text></Box>
<Box marginBottom={2}><Text>Bottom</Text></Box>
<Box marginLeft={2}><Text>Left</Text></Box>
<Box marginRight={2}><Text>Right</Text></Box>
<Box marginX={2}><Text>Left and right</Text></Box>
<Box marginY={2}><Text>Top and bottom</Text></Box>
<Box margin={2}><Text>Top, bottom, left and right</Text></Box>

Gap

gap

Type: number
Default: 0

Size of the gap between an element's columns and rows. A shorthand for columnGap and rowGap.

<Box gap={1} width={3} flexWrap="wrap">
	<Text>A</Text>
	<Text>B</Text>
	<Text>C</Text>
</Box>
// A B
//
// C

columnGap

Type: number
Default: 0

Size of the gap between an element's columns.

<Box columnGap={1}>
	<Text>A</Text>
	<Text>B</Text>
</Box>
// A B

rowGap

Type: number
Default: 0

Size of the gap between an element's rows.

<Box flexDirection="column" rowGap={1}>
	<Text>A</Text>
	<Text>B</Text>
</Box>
// A
//
// B

Flex

flexGrow

Type: number
Default: 0

See flex-grow.

<Box>
	<Text>Label:</Text>
	<Box flexGrow={1}>
		<Text>Fills all remaining space</Text>
	</Box>
</Box>
flexShrink

Type: number
Default: 1

See flex-shrink.

<Box width={20}>
	<Box flexShrink={2} width={10}>
		<Text>Will be 1/4</Text>
	</Box>
	<Box width={10}>
		<Text>Will be 3/4</Text>
	</Box>
</Box>
flexBasis

Type: number string

See

ink (vadimdemedes/ink)

hooks
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40.1K ·GitHub
Ink
What is this?Ink is React for the terminal: a library for building interactive command-line apps out of components, with the same component-based UI experience React offers in the browser.
Is it a framework I adopt wholesale, or a library I add to my own project?A library: Ink is a custom React renderer you install from npm into a Node.js project. Your CLI is a normal Node process, and Ink draws your component tree in the terminal.
How do I get a first app running?Run create-ink-app to scaffold a ready-made CLI, or create a TypeScript project and install Ink from npm. Mind that this README documents the upcoming version, while stable releases ship on npm.
What do I need installed before anything runs?Node.js — the upcoming version requires Node 22 or newer. Plain-JavaScript projects also need Babel with @babel/preset-react, or import-jsx to transpile JSX on the fly.
Any gotchas I should expect?Every piece of text must sit inside a Text component, and the app stays alive only while the event loop is busy — a component tree with no async work renders once and exits immediately.
Is it production-proven or an experiment?Battle-tested at scale: Claude Code, Gemini CLI, GitHub Copilot CLI, Shopify CLI, Cloudflare's Wrangler, Prisma and Gatsby all build on Ink.
Where do Ink apps actually run?Anywhere Node.js runs — Windows, macOS and Linux terminals. There is no browser involved; everything renders as terminal output.
How do layout and styling work without HTML and CSS?Ink uses the Yoga Flexbox layout engine, so CSS-like properties — width, height, padding, margin, gap, flexGrow — work on every Box, and each element behaves like a flex container. Colors, bold, underline and truncation are props on Text, styled via chalk.
How do I handle keyboard input and quitting?The useInput hook listens for key presses and usePaste handles pasted text. Ctrl+C exits by default via exitOnCtrlC; you can also call exit() from useApp or unmount() on the object returned by render().
Can I test and debug the UI like a web app?Yes. The README documents a Testing section, using React Devtools, and Screen Reader Support, so you can inspect the component tree and assert rendered output.
What are similar projects?Inquirer.js, opentui, cz-cli, yoga, styled-components, react, proton-native, chakra-ui
Which topics is it in?flexbox, layout, jsx, hooks, interactive, ui-library, component-library, tui, command-line, ui, react, npm
Creator
vadimdemedes
Size
2.4 MB
Stars
40.1K
Updated
CommitOct 03Releasev8.0.0Oct 03
Age
9y
Commits · 90 Days