ink

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<div align="center"> <br> <br> <img width="240" alt="Ink" src="media/logo.png"> <br> <br> <br> </div>

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

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 props are available in Ink as well. If you are already familiar with React, you already know Ink.

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

Note: This is documentation for Ink 4 and 5. If you're looking for docs on Ink 3, check out this release.

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<div align="center"> <p> <p> ^{<a href="https://opencollective.com/vadimdemedes">My open source work is supported by the community ❤️</a>} </p> </p> </div>

Install

npm install ink react

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 />);

<img src="media/demo.svg" width="600">

You can also check it out live on repl.it sandbox. Feel free to play around with the code and fork this repl at https://repl.it/@vadimdemedes/ink-counter-demo.

Who's Using Ink?

• GitHub Copilot for CLI - Just say what you want the shell to do.
• Cloudflare's Wrangler - The CLI for Cloudflare Workers.
• Linear - Linear built an internal CLI for managing deployments, configs and other housekeeping tasks.
• Gatsby - Gatsby is a modern web framework for blazing fast websites.
• tap - A Test-Anything-Protocol library for JavaScript.
• Terraform CDK - CDK (Cloud Development Kit) for HashiCorp Terraform.
• Specify CLI - Automate the distribution of your design tokens.
• Twilio's SIGNAL - CLI for Twilio's SIGNAL conference. Blog post.
• Typewriter - Generates strongly-typed Segment analytics clients from arbitrary JSON Schema.
• Prisma - The unified data layer for modern applications.
• Blitz - The Fullstack React Framework.
• New York Times - NYT uses Ink kyt - a toolkit that encapsulates and manages the configuration for web apps.
• tink - Next-generation runtime and package manager.
• Inkle - Wordle game.
• loki - Visual regression testing for Storybook.
• Bit - Build, distribute and collaborate on components.
• Remirror - Your friendly, world-class editor toolkit.
• Prime - Open source GraphQL CMS.
• Splash - Observe the splash zone of a change across the Shopify's Polaris component library.
• emoj - Find relevant emojis.
• emma - Find and install npm packages.
• npm-check-extras - Check for outdated and unused dependencies, and run update/delete action over selected ones.
• swiff - Multi-environment command line tools for time-saving web developers.
• share - Quickly share files.
• Kubelive - CLI for Kubernetes to provide live data about the cluster and its resources.
• changelog-view - View changelogs.
• cfpush - An interactive Cloud Foundry tutorial.
• startd - Turn your React component into a web app.
• wiki-cli - Search Wikipedia and read summaries.
• garson - Build interactive config-based command-line interfaces.
• git-contrib-calendar - Display a contributions calendar for any git repository.
• gitgud - An interactive command-line GUI for Git.
• Autarky - Find and delete old node_modules directories in order to free up disk space.
• fast-cli - Test your download and upload speed.
• tasuku - Minimal task runner.
• mnswpr - Minesweeper game.
• lrn - Learning by repetition.
• turdle - Wordle game.
• Shopify CLI - Build apps, themes, and storefronts for Shopify.
• ToDesktop CLI - An all-in-one platform for building Electron apps.
• Walle - Full-featured crypto wallet for EVM networks.
• Sudoku - Sudoku game.

Contents

• Getting Started
• Components
  • <Text>
  • <Box>
  • <Newline>
  • <Spacer>
  • <Static>
  • <Transform>
• Hooks
  • useInput
  • useApp
  • useStdin
  • useStdout
  • useStderr
  • useFocus
  • useFocusManager
• API
• Testing
• Using React Devtools
• Useful Components
• Useful Hooks
• Examples

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

<details><summary>Manual JavaScript setup</summary> <p> 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.

</p> </details>

Ink uses Yoga - a Flexbox layout engine to build great user interfaces for your CLIs using familiar CSS-like props 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 each <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.

Components

<Text>

This component can display text, and change its style to make it bold, underline, 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>

<img src="media/text-color.jpg" width="247">

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>

<img src="media/text-backgroundColor.jpg" width="226">

dimColor

Type: boolean
Default: false

Dim the color (emit a small amount of light).

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

<img src="media/text-dimColor.jpg" width="138">

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

Inverse background and foreground colors.

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

<img src="media/text-inverse.jpg" width="138">

wrap

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

This property tells Ink to wrap or truncate text if its width is larger than container. If wrap is passed (by default), Ink will wrap text and split it into multiple lines. If truncate-* is passed, Ink will truncate text instead, which will result in one line of text with the rest cut off.

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

// `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 in percent, which will calculate the width based on the width of 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 in percent, which will calculate the height based on the height of 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

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

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