mirrors/ink

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 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.

^{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?

Claude Code - An agentic coding tool made by Anthropic.
Gemini CLI - An agentic coding tool made by Google.
GitHub Copilot CLI - Just say what you want the shell to do.
Canva CLI - CLI for creating and managing Canva Apps.
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 - Cloud Development Kit (CDK) 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’s kyt - a toolkit that encapsulates and manages the configuration for web apps.
tink - A next-generation runtime and package manager.
Inkle - A Wordle game.
loki - Visual regression testing tool for Storybook.
Bit - Build, distribute, and collaborate on components.
Remirror - Your friendly, world-class editor toolkit.
Prime - Open-source GraphQL CMS.
emoj - Find relevant emojis.
emma - Find and install npm packages easily.
npm-check-extras - Check for outdated and unused dependencies, and run update/delete actions on selected ones.
swiff - Multi-environment command-line tools for time-saving web developers.
share - Share files quickly.
Kubelive - A CLI for Kubernetes that provides live data about the cluster and its resources.
changelog-view - View changelogs.
cfpush - Interactive Cloud Foundry tutorial.
startd - Turn your React component into a web app.
wiki-cli - Search Wikipedia and read article summaries.
garson - Build interactive, config-based command-line interfaces.
git-contrib-calendar - Display a contributions calendar for any Git repository.
gitgud - Interactive command-line GUI for Git.
Autarky - Find and delete old node_modules directories to free up disk space.
fast-cli - Test your download and upload speeds.
tasuku - Minimal task runner.
mnswpr - A Minesweeper game.
lrn - Learning by repetition.
turdle - A Wordle game.
Shopify CLI - Build apps, themes, and storefronts for the Shopify platform.
ToDesktop CLI - All-in-one platform for building Electron apps.
Walle - A full-featured crypto wallet for EVM networks.
Sudoku - A Sudoku game.
Sea Trader - A Taipan!-inspired trading simulator game.
srtd - Live-reloading SQL templates for Supabase projects.
tweakcc - Customize your Claude Code styling.
argonaut - Manage Argo CD resources.
Qodo Command - Build, run, and manage AI agents.
Nanocoder - A community-built, local-first AI coding agent with multi-provider support.
dev3000 - An AI agent MCP orchestrator and developer browser.
Neovate Code - An agentic coding tool made by AntGroup.
instagram-cli - Instagram client.
ElevenLabs CLI - ElevenLabs agents client.
SSH AI Chat - Chat with AI over SSH.

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

Getting Started
App Lifecycle
Components
Hooks
API
Testing
Using React Devtools
Screen Reader Support
Useful Components
Useful Hooks
Recipes
Examples
Continuous Integration

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 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 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'

// `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 flex-basis.

<Box width={6}>
    <Box flexBasis={3}>
        <Text>X</Text>
    </Box>
    <Text>Y</Text>
</Box>
//=> 'X  Y'

<Box width={6}>
    <Box flexBasis="50%">
        <Text>X</Text>
    </Box>
    <Text>Y</Text>
</Box>
//=> 'X  Y'

flexDirection

Type: string
Allowed values: row row-reverse column column-reverse

See flex-direction.

<Box>
    <Box marginRight={1}>
        <Text>X</Text>
    </Box>
    <Text>Y</Text>
</Box>
// X Y

<Box flexDirection="row-reverse">
    <Text>X</Text>
    <Box marginRight={1}>
        <Text>Y</Text>
    </Box>
</Box>
// Y X

<Box flexDirection="column">
    <Text>X</Text>
    <Text>Y</Text>
</Box>
// X
// Y

<Box flexDirection="column-reverse">
    <Text>X</Text>
    <Text>Y</Text>
</Box>
// Y
// X

flexWrap

Type: string
Allowed values: nowrap wrap wrap-reverse

See flex-wrap.

<Box width={2} flexWrap="wrap">
    <Text>A</Text>
    <Text>BC</Text>
</Box>
// A
// B C

<Box flexDirection="column" height={2} flexWrap="wrap">
    <Text>A</Text>
    <Text>B</Text>
    <Text>C</Text>
</Box>
// A C
// B

alignItems

Type: string
Allowed values: flex-start center flex-end stretch baseline

See align-items.

<Box alignItems="flex-start">
    <Box marginRight={1}>
        <Text>X</Text>
    </Box>
    <Text>
        A
        <Newline/>
        B
        <Newline/>
        C
    </Text>
</Box>
// X A
//   B
//   C

<Box alignItems="center">
    <Box marginRight={1}>
        <Text>X</Text>
    </Box>
    <Text>
        A
        <Newline/>
        B
        <Newline/>
        C
    </Text>
</Box>
//   A
// X B
//   C

<Box alignItems="flex-end">
    <Box marginRight={1}>
        <Text>X</Text>
    </Box>
    <Text>
        A
        <Newline/>
        B
        <Newline/>
        C
    </Text>
</Box>
//   A
//   B
// X C

alignSelf

Type: string
Default: auto
Allowed values: auto flex-start center flex-end stretch baseline

See align-self.

<Box height={3}>
    <Box alignSelf="flex-start">
        <Text>X</Text>
    </Box>
</Box>
// X
//
//

<Box height={3}>
    <Box alignSelf="center">
        <Text>X</Text>
    </Box>
</Box>
//
// X
//

<Box height={3}>
    <Box alignSelf="flex-end">
        <Text>X</Text>
    </Box>
</Box>
//
//
// X

alignContent

Type: string
Default: flex-start
Allowed values: flex-start flex-end center stretch space-between space-around space-evenly

Defines alignment between flex lines on the cross axis when flexWrap creates multiple lines. See align-content. Unlike CSS (stretch), Ink defaults to flex-start so wrapped lines stay compact and fixed-height boxes don’t gain unexpected empty rows unless you opt in to stretching.

justifyContent

Type: string
Allowed values: flex-start center flex-end space-between space-around space-evenly

See justify-content.

<Box justifyContent="flex-start">
    <Text>X</Text>
</Box>
// [X      ]

<Box justifyContent="center">
    <Text>X</Text>
</Box>
// [   X   ]

<Box justifyContent="flex-end">
    <Text>X</Text>
</Box>
// [      X]

<Box justifyContent="space-between">
    <Text>X</Text>
    <Text>Y</Text>
</Box>
// [X      Y]

<Box justifyContent="space-around">
    <Text>X</Text>
    <Text>Y</Text>
</Box>
// [  X   Y  ]

<Box justifyContent="space-evenly">
    <Text>X</Text>
    <Text>Y</Text>
</Box>
// [   X   Y   ]

Position

position

Type: string
Allowed values: relative absolute static
Default: relative

Controls how the element is positioned.

When position is static, top, right, bottom, and left are ignored.

top

Type: number string

Top offset for positioned elements. You can also set it as a percentage of the parent size.

right

Type: number string

Right offset for positioned elements. You can also set it as a percentage of the parent size.

bottom

Type: number string

Bottom offset for positioned elements. You can also set it as a percentage of the parent size.

left

Type: number string

Left offset for positioned elements. You can also set it as a percentage of the parent size.

Visibility

display

Type: string
Allowed values: flex none
Default: flex

Set this property to none to hide the element.

overflowX

Type: string
Allowed values: visible hidden
Default: visible

Behavior for an element’s overflow in the horizontal direction.

overflowY

Type: string
Allowed values: visible hidden
Default: visible

Behavior for an element’s overflow in the vertical direction.

overflow

Type: string
Allowed values: visible hidden
Default: visible

A shortcut for setting overflowX and overflowY at the same time.

Borders

borderStyle

Type: string
Allowed values: single double round bold singleDouble doubleSingle classic | BoxStyle

Add a border with a specified style. If borderStyle is undefined (the default), no border will be added. Ink uses border styles from the cli-boxes module.

<Box flexDirection="column">
    <Box>
        <Box borderStyle="single" marginRight={2}>
            <Text>single</Text>
        </Box>

        <Box borderStyle="double" marginRight={2}>
            <Text>double</Text>
        </Box>

        <Box borderStyle="round" marginRight={2}>
            <Text>round</Text>
        </Box>

        <Box borderStyle="bold">
            <Text>bold</Text>
        </Box>
    </Box>

    <Box marginTop={1}>
        <Box borderStyle="singleDouble" marginRight={2}>
            <Text>singleDouble</Text>
        </Box>

        <Box borderStyle="doubleSingle" marginRight={2}>
            <Text>doubleSingle</Text>
        </Box>

        <Box borderStyle="classic">
            <Text>classic</Text>
        </Box>
    </Box>
</Box>

Alternatively, pass a custom border style like so:

<Box
    borderStyle={{
        topLeft: '↘',
        top: '↓',
        topRight: '↙',
        left: '→',
        bottomLeft: '↗',
        bottom: '↑',
        bottomRight: '↖',
        right: '←'
    }}
>
    <Text>Custom</Text>
</Box>

See example in examples/borders.

borderColor

Type: string

Change border color. A shorthand for setting borderTopColor, borderRightColor, borderBottomColor, and borderLeftColor.

<Box borderStyle="round" borderColor="green">
    <Text>Green Rounded Box</Text>
</Box>

borderTopColor

Type: string

Change top border color. Accepts the same values as color in <Text> component.

<Box borderStyle="round" borderTopColor="green">
    <Text>Hello world</Text>
</Box>

borderRightColor

Type: string

Change the right border color. Accepts the same values as color in <Text> component.

<Box borderStyle="round" borderRightColor="green">
    <Text>Hello world</Text>
</Box>

borderBottomColor

Type: string

Change the bottom border color. Accepts the same values as color in <Text> component.

<Box borderStyle="round" borderBottomColor="green">
    <Text>Hello world</Text>
</Box>

borderLeftColor

Type: string

Change the left border color. Accepts the same values as color in <Text> component.

<Box borderStyle="round" borderLeftColor="green">
    <Text>Hello world</Text>
</Box>

borderDimColor

Type: boolean
Default: false

Dim the border color. A shorthand for setting borderTopDimColor, borderBottomDimColor, borderLeftDimColor, and borderRightDimColor.

<Box borderStyle="round" borderDimColor>
    <Text>Hello world</Text>
</Box>

borderTopDimColor

Type: boolean
Default: false

Dim the top border color.

<Box borderStyle="round" borderTopDimColor>
    <Text>Hello world</Text>
</Box>

borderBottomDimColor

Type: boolean
Default: false

Dim the bottom border color.

<Box borderStyle="round" borderBottomDimColor>
    <Text>Hello world</Text>
</Box>

borderLeftDimColor

Type: boolean
Default: false

Dim the left border color.

<Box borderStyle="round" borderLeftDimColor>
    <Text>Hello world</Text>
</Box>

borderRightDimColor

Type: boolean
Default: false

Dim the right border color.

<Box borderStyle="round" borderRightDimColor>
    <Text>Hello world</Text>
</Box>

borderTop

Type: boolean
Default: true

Determines whether the top border is visible.

borderRight

Type: boolean
Default: true

Determines whether the right border is visible.

borderBottom

Type: boolean
Default: true

Determines whether the bottom border is visible.

borderLeft

Type: boolean
Default: true

Determines whether the left border is visible.

Background

backgroundColor

Type: string

Background color for the element.

Accepts the same values as color in the <Text> component.

<Box flexDirection="column">
    <Box backgroundColor="red" width={20} height={5} alignSelf="flex-start">
        <Text>Red background</Text>
    </Box>

    <Box backgroundColor="#FF8800" width={20} height={3} marginTop={1} alignSelf="flex-start">
        <Text>Orange background</Text>
    </Box>

    <Box backgroundColor="rgb(0, 255, 0)" width={20} height={3} marginTop={1} alignSelf="flex-start">
        <Text>Green background</Text>
    </Box>
</Box>

The background color fills the entire <Box> area and is inherited by child <Text> components unless they specify their own backgroundColor.

<Box backgroundColor="blue" alignSelf="flex-start">
    <Text>Blue inherited </Text>
    <Text backgroundColor="yellow">Yellow override </Text>
    <Text>Blue inherited again</Text>
</Box>

Background colors work with borders and padding:

<Box backgroundColor="cyan" borderStyle="round" padding={1} alignSelf="flex-start">
    <Text>Background with border and padding</Text>
</Box>

See example in examples/box-backgrounds.

`<Newline>`

Adds one or more newline (\n) characters. Must be used within <Text> components.

count

Type: number
Default: 1

Number of newlines to insert.

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

const Example = () => (
    <Text>
        <Text color="green">Hello</Text>
        <Newline />
        <Text color="red">World</Text>
    </Text>
);

render(<Example />);

Output:

Hello
World

`<Spacer>`

A flexible space that expands along the major axis of its containing layout. It’s useful as a shortcut for filling all the available space between elements.

For example, using <Spacer> in a <Box> with default flex direction (row) will position “Left” on the left side and will push “Right” to the right side.

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

const Example = () => (
    <Box>
        <Text>Left</Text>
        <Spacer />
        <Text>Right</Text>
    </Box>
);

render(<Example />);

In a vertical flex direction (column), it will position “Top” at the top of the container and push “Bottom” to the bottom. Note that the container needs to be tall enough to see this in effect.

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

const Example = () => (
    <Box flexDirection="column" height={10}>
        <Text>Top</Text>
        <Spacer />
        <Text>Bottom</Text>
    </Box>
);

render(<Example />);

`<Static>`

<Static> component permanently renders its output above everything else. It’s useful for displaying activity like completed tasks or logs - things that don’t change after they’re rendered (hence the name “Static”).

It’s preferred to use <Static> for use cases like these when you can’t know or control the number of items that need to be rendered.

For example, Tap uses <Static> to display a list of completed tests. Gatsby uses it to display a list of generated pages while still displaying a live progress bar.

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

const Example = () => {
    const [tests, setTests] = useState([]);

    useEffect(() => {
        let completedTests = 0;
        let timer;

        const run = () => {
            // Fake 10 completed tests
            if (completedTests++ < 10) {
                setTests(previousTests => [
                    ...previousTests,
                    {
                        id: previousTests.length,
                        title: `Test #${previousTests.length + 1}`
                    }
                ]);

                timer = setTimeout(run, 100);
            }
        };

        run();

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

    return (
        <>
            {/* This part will be rendered once to the terminal */}
            <Static items={tests}>
                {test => (
                    <Box key={test.id}>
                        <Text color="green">✔ {test.title}</Text>
                    </Box>
                )}
            </Static>

            {/* This part keeps updating as state changes */}
            <Box marginTop={1}>
                <Text dimColor>Completed tests: {tests.length}</Text>
            </Box>
        </>
    );
};

render(<Example />);

[!NOTE] <Static> only renders new items in the items prop and ignores items that were previously rendered. This means that when you add new items to the items array, changes you make to previous items will not trigger a rerender.

See examples/static for an example usage of <Static> component.

items

Type: Array

Array of items of any type to render using the function you pass as a component child.

style

Type: object

Styles to apply to a container of child elements. See <Box> for supported properties.

<Static items={...} style={{padding: 1}}>
    {...}
</Static>

children(item)

Type: Function

Function that is called to render every item in the items array. The first argument is the item itself, and the second argument is the index of that item in the items array.

Note that a key must be assigned to the root component.

<Static items={['a', 'b', 'c']}>
    {(item, index) => {
        // This function is called for every item in ['a', 'b', 'c']
        // `item` is 'a', 'b', 'c'
        // `index` is 0, 1, 2
        return (
            <Box key={index}>
                <Text>Item: {item}</Text>
            </Box>
        );
    }}
</Static>

`<Transform>`

Transform a string representation of React components before they’re written to output. For example, you might want to apply a gradient to text, add a clickable link, or create some text effects. These use cases can’t accept React nodes as input; they expect a string. That’s what the <Transform> component does: it gives you an output string of its child components and lets you transform it in any way.

[!NOTE] <Transform> must be applied only to <Text> children components and shouldn’t change the dimensions of the output; otherwise, the layout will be incorrect.

[!IMPORTANT] When children use <Text> styling props (e.g. color, bold), the string passed to transform will contain ANSI escape codes. If your transform manipulates whitespace or does string operations like .trim(), you may need to use ANSI-aware methods (e.g. from slice-ansi or strip-ansi).

import {render, Transform} from 'ink';

const Example = () => (
    <Transform transform={output => output.toUpperCase()}>
        <Text>Hello World</Text>
    </Transform>
);

render(<Example />);

Since the transform function converts all characters to uppercase, the final output rendered to the terminal will be “HELLO WORLD”, not “Hello World”.

When the output wraps to multiple lines, it can be helpful to know which line is being processed.

For example, to implement a hanging indent component, you can indent all the lines except for the first.

import {render, Transform} from 'ink';

const HangingIndent = ({indent = 4, children}) => (
    <Transform
        transform={(line, index) =>
            index === 0 ? line : ' '.repeat(indent) + line
        }
    >
        {children}
    </Transform>
);

const text =
    'WHEN I WROTE the following pages, or rather the bulk of them, ' +
    'I lived alone, in the woods, a mile from any neighbor, in a ' +
    'house which I had built myself, on the shore of Walden Pond, ' +
    'in Concord, Massachusetts, and earned my living by the labor ' +
    'of my hands only. I lived there two years and two months. At ' +
    'present I am a sojourner in civilized life again.';

render(
    <HangingIndent indent={4}>
        {text}
    </HangingIndent>
);

transform(outputLine, index)

Type: Function

Function that transforms children output. It accepts children and must return transformed children as well.

children

Type: string

Output of child components.

index

Type: number

The zero-indexed line number of the line that’s currently being transformed.

Hooks

useInput(inputHandler, options?)

A React hook that returns void and handles user input. It’s a more convenient alternative to using useStdin and listening for data events. The callback you pass to useInput is called for each character when the user enters any input. However, if the user pastes text and it’s more than one character, the callback will be called only once, and the whole string will be passed as input. You can find a full example of using useInput at examples/use-input.

import {useInput} from 'ink';

const UserInput = () => {
    useInput((input, key) => {
        if (input === 'q') {
            // Exit program
        }

        if (key.leftArrow) {
            // Left arrow key pressed
        }
    });

    return …
};

inputHandler(input, key)

Type: Function

The handler function that you pass to useInput receives two arguments:

input

Type: string

The input that the program received.

key

Type: object

Handy information about a key that was pressed.

key.leftArrow

key.rightArrow

key.upArrow

key.downArrow

Type: boolean
Default: false

If an arrow key was pressed, the corresponding property will be true. For example, if the user presses the left arrow key, key.leftArrow equals true.

key.return

Type: boolean
Default: false

Return (Enter) key was pressed.

key.escape

Type: boolean
Default: false

Escape key was pressed.

key.ctrl

Type: boolean
Default: false

Ctrl key was pressed.

key.shift

Type: boolean
Default: false

Shift key was pressed.

key.tab

Type: boolean
Default: false

Tab key was pressed.

key.backspace

Type: boolean
Default: false

Backspace key was pressed.

key.delete

Type: boolean
Default: false

Delete key was pressed.

key.pageDown

key.pageUp

Type: boolean
Default: false

If the Page Up or Page Down key was pressed, the corresponding property will be true. For example, if the user presses Page Down, key.pageDown equals true.

key.home

key.end

Type: boolean
Default: false

If the Home or End key was pressed, the corresponding property will be true. For example, if the user presses End, key.end equals true.

key.meta

Type: boolean
Default: false

Meta key was pressed.

key.super

Type: boolean
Default: false

Super key (Cmd on macOS, Win on Windows) was pressed. Requires kitty keyboard protocol.

key.hyper

Type: boolean
Default: false

Hyper key was pressed. Requires kitty keyboard protocol.

key.capsLock

Type: boolean
Default: false

Caps Lock was active. Requires kitty keyboard protocol.

key.numLock

Type: boolean
Default: false

Num Lock was active. Requires kitty keyboard protocol.

key.eventType

Type: 'press' | 'repeat' | 'release'
Default: undefined

The type of key event. Only available with kitty keyboard protocol. Without the protocol, this property is undefined.

options

Type: object

isActive

Type: boolean
Default: true

Enable or disable capturing of user input. Useful when there are multiple useInput hooks used at once to avoid handling the same input several times.

usePaste(handler, options?)

A React hook that calls handler whenever the user pastes text. Bracketed paste mode (\x1b[?2004h) is automatically enabled while the hook is active, so pasted text arrives as a single string rather than being misinterpreted as individual key presses.

usePaste and useInput can be used together in the same component. They operate on separate event channels, so paste content is never forwarded to useInput handlers when usePaste is active.

import {useInput, usePaste} from 'ink';

const MyInput = () => {
    useInput((input, key) => {
        // Only receives typed characters and key events, not pasted text.
        if (key.return) {
            // Submit
        }
    });

    usePaste((text) => {
        // Receives the full pasted string, including newlines.
        console.log('Pasted:', text);
    });

    return …
};

handler(text)

Type: Function

Called with the full pasted string whenever the user pastes text. The string is delivered verbatim — newlines, escape sequences, and other special characters are preserved exactly as pasted.

text

Type: string

The pasted text.

options

Type: object

isActive

Type: boolean
Default: true

Enable or disable the paste handler. Useful when multiple components use usePaste and only one should be active at a time.

useApp()

A React hook that returns app lifecycle methods.

exit(errorOrResult?)

Type: Function

Exit (unmount) the whole Ink app.

errorOrResult

Type: Error | unknown

Optional value that controls how waitUntilExit settles:

exit() resolves with undefined.
exit(error) rejects when error is an Error.
exit(value) resolves with value.

import {useEffect} from 'react';
import {useApp} from 'ink';

const Example = () => {
    const {exit} = useApp();

    // Exit the app after 5 seconds
    useEffect(() => {
        setTimeout(() => {
            exit();
        }, 5000);
    }, [exit]);

    return …
};

waitUntilRenderFlush()

Type: Function

Returns a promise that settles after pending render output is flushed to stdout.

import {useEffect} from 'react';
import {useApp} from 'ink';

const Example = () => {
    const {waitUntilRenderFlush} = useApp();

    useEffect(() => {
        void (async () => {
            await waitUntilRenderFlush();
            runNextCommand();
        })();
    }, [waitUntilRenderFlush]);

    return …;
};

useStdin()

A React hook that returns the stdin stream and stdin-related utilities.

stdin

Type: stream.Readable
Default: process.stdin

The stdin stream passed to render() in options.stdin, or process.stdin by default. Useful if your app needs to handle user input.

import {useStdin} from 'ink';

const Example = () => {
    const {stdin} = useStdin();

    return …
};

isRawModeSupported

Type: boolean

A boolean flag determining if the current stdin supports setRawMode. A component using setRawMode might want to use isRawModeSupported to nicely fall back in environments where raw mode is not supported.

import {useStdin} from 'ink';

const Example = () => {
    const {isRawModeSupported} = useStdin();

    return isRawModeSupported ? (
        <MyInputComponent />
    ) : (
        <MyComponentThatDoesntUseInput />
    );
};

setRawMode(isRawModeEnabled)

Type: function

isRawModeEnabled

Type: boolean

See setRawMode. Ink exposes this function to be able to handle Ctrl+C, that’s why you should use Ink’s setRawMode instead of process.stdin.setRawMode.

Warning: This function will throw unless the current stdin supports setRawMode. Use isRawModeSupported to detect setRawMode support.

import {useStdin} from 'ink';

const Example = () => {
    const {setRawMode} = useStdin();

    useEffect(() => {
        setRawMode(true);

        return () => {
            setRawMode(false);
        };
    });

    return …
};

useStdout()

A React hook that returns the stdout stream where Ink renders your app and stdout-related utilities.

stdout

Type: stream.Writable
Default: process.stdout

import {useStdout} from 'ink';

const Example = () => {
    const {stdout} = useStdout();

    return …
};

write(data)

Write any string to stdout while preserving Ink’s output. It’s useful when you want to display external information outside of Ink’s rendering and ensure there’s no conflict between the two. It’s similar to <Static>, except it can’t accept components; it only works with strings.

data

Type: string

Data to write to stdout.

import {useStdout} from 'ink';

const Example = () => {
    const {write} = useStdout();

    useEffect(() => {
        // Write a single message to stdout, above Ink's output
        write('Hello from Ink to stdout\n');
    }, []);

    return …
};

See additional usage example in examples/use-stdout.

useBoxMetrics(ref)

A React hook that returns the current layout metrics for a tracked box element. It updates when layout changes (for example terminal resize, sibling/content changes, or position changes).

Use hasMeasured to detect when the currently tracked element has been measured.

ref

Type: React.RefObject<DOMElement>

A ref to the <Box> element to track.

import {useRef} from 'react';
import {Box, Text, useBoxMetrics} from 'ink';

const Example = () => {
    const ref = useRef(null);
    const {width, height, left, top, hasMeasured} = useBoxMetrics(ref);

    return (
        <Box ref={ref}>
            <Text>
                {hasMeasured ? `${width}x${height} at ${left},${top}` : 'Measuring...'}
            </Text>
        </Box>
    );
};

width

Type: number

Element width.

height

Type: number

Element height.

left

Type: number

Distance from the left edge of the parent.

top

Type: number

Distance from the top edge of the parent.

hasMeasured

Type: boolean

Whether the currently tracked element has been measured.

[!NOTE] The hook returns {width: 0, height: 0, left: 0, top: 0} until the first layout pass completes. It also returns zeros when the tracked ref is detached.

useStderr()

A React hook that returns the stderr stream and stderr-related utilities.

stderr

Type: stream.Writable
Default: process.stderr

Stderr stream.

import {useStderr} from 'ink';

const Example = () => {
    const {stderr} = useStderr();

    return …
};

write(data)

Write any string to stderr while preserving Ink’s output.

It’s useful when you want to display external information outside of Ink’s rendering and ensure there’s no conflict between the two. It’s similar to <Static>, except it can’t accept components; it only works with strings.

data

Type: string

Data to write to stderr.

import {useStderr} from 'ink';

const Example = () => {
    const {write} = useStderr();

    useEffect(() => {
        // Write a single message to stderr, above Ink's output
        write('Hello from Ink to stderr\n');
    }, []);

    return …
};

useWindowSize()

A React hook that returns the current terminal dimensions and re-renders the component whenever the terminal is resized.

import {Text, useWindowSize} from 'ink';

const Example = () => {
    const {columns, rows} = useWindowSize();

    return <Text>{columns}x{rows}</Text>;
};

columns

Type: number

Number of columns (horizontal character cells).

rows

Type: number

Number of rows (vertical character cells).

useFocus(options?)

A React hook that returns focus state and focus controls for the current component. A component that uses the useFocus hook becomes “focusable” to Ink, so when the user presses Tab, Ink will switch focus to this component. If there are multiple components that execute the useFocus hook, focus will be given to them in the order in which these components are rendered. This hook returns an object with an isFocused boolean property, which determines whether this component is focused.

options

autoFocus

Type: boolean
Default: false

Auto-focus this component if there’s no active (focused) component right now.

isActive

Type: boolean
Default: true

Enable or disable this component’s focus, while still maintaining its position in the list of focusable components. This is useful for inputs that are temporarily disabled.

id

Type: string
Required: false

Set a component’s focus ID, which can be used to programmatically focus the component. This is useful for large interfaces with many focusable elements to avoid having to cycle through all of them.

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

const Example = () => {
    const {isFocused} = useFocus();

    return <Text>{isFocused ? 'I am focused' : 'I am not focused'}</Text>;
};

render(<Example />);

See example in examples/use-focus and examples/use-focus-with-id.

useFocusManager()

A React hook that returns methods to manage focus across focusable components.

enableFocus()

Enable focus management for all components.

[!NOTE] You don’t need to call this method manually unless you’ve disabled focus management. Focus management is enabled by default.

import {useFocusManager} from 'ink';

const Example = () => {
    const {enableFocus} = useFocusManager();

    useEffect(() => {
        enableFocus();
    }, []);

    return …
};

disableFocus()

Disable focus management for all components. The currently active component (if there’s one) will lose its focus.

import {useFocusManager} from 'ink';

const Example = () => {
    const {disableFocus} = useFocusManager();

    useEffect(() => {
        disableFocus();
    }, []);

    return …
};

focusNext()

Switch focus to the next focusable component. If there’s no active component right now, focus will be given to the first focusable component. If the active component is the last in the list of focusable components, focus will be switched to the first focusable component.

[!NOTE] Ink calls this method when user presses Tab.

import {useFocusManager} from 'ink';

const Example = () => {
    const {focusNext} = useFocusManager();

    useEffect(() => {
        focusNext();
    }, []);

    return …
};

focusPrevious()

Switch focus to the previous focusable component. If there’s no active component right now, focus will be given to the first focusable component. If the active component is the first in the list of focusable components, focus will be switched to the last focusable component.

[!NOTE] Ink calls this method when user presses Shift+Tab.

import {useFocusManager} from 'ink';

const Example = () => {
    const {focusPrevious} = useFocusManager();

    useEffect(() => {
        focusPrevious();
    }, []);

    return …
};

focus(id)

id

Type: string

Switch focus to the component with the given id. If there’s no component with that ID, focus is not changed.

import {useFocusManager, useInput} from 'ink';

const Example = () => {
    const {focus} = useFocusManager();

    useInput(input => {
        if (input === 's') {
            // Focus the component with focus ID 'someId'
            focus('someId');
        }
    });

    return …
};

activeId

Type: string | undefined

The ID of the currently focused component, or undefined if no component is focused.

import {Text, useFocusManager} from 'ink';

const Example = () => {
    const {activeId} = useFocusManager();

    return <Text>Focused: {activeId ?? 'none'}</Text>;
};

useCursor()

A React hook that returns methods to control the terminal cursor position after each render. This is essential for IME (Input Method Editor) support, where the composing character is displayed at the cursor location.

import {useState} from 'react';
import {Box, Text, useCursor} from 'ink';
import stringWidth from 'string-width';

const TextInput = () => {
    const [text, setText] = useState('');
    const {setCursorPosition} = useCursor();

    const prompt = '> ';
    setCursorPosition({x: stringWidth(prompt + text), y: 1});

    return (
        <Box flexDirection="column">
            <Text>Type here:</Text>
            <Text>{prompt}{text}</Text>
        </Box>
    );
};

setCursorPosition(position)

Set the cursor position relative to the Ink output. Pass undefined to hide the cursor.

position

Type: object | undefined

Use string-width to calculate x for strings containing wide characters (CJK, emoji).

See a full example at examples/cursor-ime.

x

Type: number

Column position (0-based).

y

Type: number

Row position from the top of the Ink output (0 = first line).

useIsScreenReaderEnabled()

A React hook that returns whether a screen reader is enabled. This is useful when you want to render different output for screen readers.

import {useIsScreenReaderEnabled, Text} from 'ink';

const Example = () => {
    const isScreenReaderEnabled = useIsScreenReaderEnabled();

    return (
        <Text>
            {isScreenReaderEnabled
                ? 'Screen reader is enabled'
                : 'Screen reader is disabled'}
        </Text>
    );
};

API

render(tree, options?)

Returns: Instance

Mount a component and render the output.

tree

Type: ReactNode

options

Type: object

stdout

Type: stream.Writable
Default: process.stdout

Output stream where the app will be rendered.

stdin

Type: stream.Readable
Default: process.stdin

Input stream where app will listen for input.

stderr

Type: stream.Writable
Default: process.stderr

Error stream.

exitOnCtrlC

Type: boolean
Default: true

Configure whether Ink should listen for Ctrl+C keyboard input and exit the app. This is needed in case process.stdin is in raw mode, because then Ctrl+C is ignored by default and the process is expected to handle it manually.

patchConsole

Type: boolean
Default: true

Patch console methods to ensure console output doesn’t mix with Ink’s output. When any of the console.* methods are called (like console.log()), Ink intercepts their output, clears the main output, renders output from the console method, and then rerenders the main output again. That way, both are visible and don’t overlap each other.

This functionality is powered by patch-console, so if you need to disable Ink’s interception of output but want to build something custom, you can use that.

onRender

Type: ({renderTime: number}) => void
Default: undefined

Runs the given callback after each render and re-render with render metrics. This callback runs after Ink commits a frame, but it does not wait for stdout/stderr stream callbacks. To run code after output is flushed, use waitUntilRenderFlush().

isScreenReaderEnabled

Type: boolean
Default: process.env['INK_SCREEN_READER'] === 'true'

Enable screen reader support. See Screen Reader Support.

debug

Type: boolean
Default: false

If true, each update will be rendered as separate output, without replacing the previous one.

maxFps

Type: number
Default: 30

Maximum frames per second for render updates. This controls how frequently the UI can update to prevent excessive re-rendering. Higher values allow more frequent updates but may impact performance. Setting it to a lower value may be useful for components that update very frequently, to reduce CPU usage.

incrementalRendering

Type: boolean
Default: false

Enable incremental rendering mode which only updates changed lines instead of redrawing the entire output. This can reduce flickering and improve performance for frequently updating UIs.

concurrent

Type: boolean
Default: false

Enable React Concurrent Rendering mode.

When enabled:

Suspense boundaries work correctly with async data fetching
useTransition and useDeferredValue hooks are fully functional
Updates can be interrupted for higher priority work

render(<MyApp />, {concurrent: true});

[!NOTE] Concurrent mode changes the timing of renders. Some tests may need to use act() to properly await updates. The concurrent option only takes effect on the first render for a given stdout. If you need to change the rendering mode, call unmount() first.

interactive

Type: boolean
Default: true (false if in CI (detected via is-in-ci) or stdout.isTTY is falsy)

Override automatic interactive mode detection.

By default, Ink detects whether the environment is interactive based on CI detection and stdout.isTTY. When non-interactive, Ink skips terminal-specific features like ANSI erase sequences, cursor manipulation, synchronized output, resize handling, and kitty keyboard auto-detection. Only the final frame of non-static output is written at unmount.

Most users should not need to set this option. Use it when you have your own “interactive” detection logic that differs from the built-in behavior.

// Use your own detection logic
const isInteractive = myCustomDetection();
render(<MyApp />, {interactive: isInteractive});

kittyKeyboard

Type: object
Default: undefined

Enable the kitty keyboard protocol for enhanced keyboard input handling. When enabled, terminals that support the protocol will report additional key information including super, hyper, capsLock, numLock modifiers and eventType (press/repeat/release).

import {render} from 'ink';

render(<MyApp />, {kittyKeyboard: {mode: 'auto'}});

import {render} from 'ink';

render(<MyApp />, {
    kittyKeyboard: {
        mode: 'enabled',
        flags: ['disambiguateEscapeCodes', 'reportEventTypes'],
    },
});

kittyKeyboard.mode

Type: 'auto' | 'enabled' | 'disabled'
Default: 'auto'

'auto': Detect terminal support using a heuristic precheck (known terminals like kitty, WezTerm, Ghostty) followed by a protocol query confirmation (CSI ? u). The protocol is only enabled if the terminal responds to the query within a short timeout.
'enabled': Force enable the protocol. Both stdin and stdout must be TTYs.
'disabled': Never enable the protocol.

kittyKeyboard.flags

Type: string[]
Default: ['disambiguateEscapeCodes']

Protocol flags to request from the terminal. Pass an array of flag name strings.

Available flags:

'disambiguateEscapeCodes' - Disambiguate escape codes
'reportEventTypes' - Report key press, repeat, and release events
'reportAlternateKeys' - Report alternate key encodings
'reportAllKeysAsEscapeCodes' - Report all keys as escape codes
'reportAssociatedText' - Report associated text with key events

Behavior notes

When the kitty keyboard protocol is enabled, input handling changes in several ways:

Non-printable keys produce empty input. Keys like function keys (F1-F35), modifier-only keys (Shift, Control, Super), media keys, Caps Lock, Print Screen, and similar keys will not produce any text in the input parameter of useInput. They can still be detected via the key object properties.
Ctrl+letter shortcuts work as expected. When the terminal sends Ctrl+letter as codepoint 1-26 (the kitty CSI-u alternate form), input is set to the letter name (e.g. 'c' for Ctrl+C) and key.ctrl is true. This ensures exitOnCtrlC and custom Ctrl+letter handlers continue to work regardless of which codepoint form the terminal uses.
Key disambiguation. The protocol allows the terminal to distinguish between keys that normally produce the same escape sequence. For example:
- Ctrl+I vs Tab - without the protocol, both produce the same byte (\x09). With the protocol, they are reported as distinct keys.
- Shift+Enter vs Enter - the shift modifier is correctly reported.
- Escape key vs Ctrl+[ - these are disambiguated.
Event types. With the reportEventTypes flag, key press, repeat, and release events are distinguished via key.eventType.

renderToString(tree, options?)

Returns: string

Render a React element to a string synchronously. Unlike render(), this function does not write to stdout, does not set up any terminal event listeners, and returns the rendered output as a string.

Useful for generating documentation, writing output to files, testing, or any scenario where you need the rendered output as a string without starting a persistent terminal application.

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

const output = renderToString(
    <Box padding={1}>
        <Text color="green">Hello World</Text>
    </Box>,
);

console.log(output);

Notes:

Terminal-specific hooks (useInput, useStdin, useStdout, useStderr, useWindowSize, useApp, useFocus, useFocusManager) return default no-op values since there is no terminal session. They will not throw, but they will not function as in a live terminal.
useEffect callbacks will execute during rendering (due to synchronous rendering mode), but state updates they trigger will not affect the returned output, which reflects the initial render.
useLayoutEffect callbacks fire synchronously during commit, so state updates they trigger will be reflected in the output.
The <Static> component is supported — its output is prepended to the dynamic output.
If a component throws during rendering, the error is propagated to the caller after cleanup.

tree

Type: ReactNode

options

Type: object

columns

Type: number
Default: 80

Width of the virtual terminal in columns. Controls where text wrapping occurs.

const output = renderToString(<Text>{'A'.repeat(100)}</Text>, {
    columns: 40,
});
// Text wraps at 40 columns

Instance

This is the object that render() returns.

rerender(tree)

Replace the previous root node with a new one or update the props of the current root node.

tree

Type: ReactNode

// Update props of the root node
const {rerender} = render(<Counter count={1} />);
rerender(<Counter count={2} />);

// Replace root node
const {rerender} = render(<OldCounter />);
rerender(<NewCounter />);

unmount()

Manually unmount the whole Ink app.

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

waitUntilExit()

Returns a promise that settles when the app is unmounted.

It resolves with the value passed to exit(value) and rejects with the error passed to exit(error). When unmount() is called manually, it settles after unmount-related stdout writes complete.

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

setTimeout(unmount, 1000);

await waitUntilExit(); // resolves after `unmount()` is called

waitUntilRenderFlush()

Returns a promise that settles after pending render output is flushed to stdout.

Useful when you need to run code only after a frame is written:

const {rerender, waitUntilRenderFlush} = render(<MyApp step="loading" />);

rerender(<MyApp step="ready" />);
await waitUntilRenderFlush(); // output for "ready" is flushed

runNextCommand();

cleanup()

Delete the internal Ink instance associated with the current stdout. This is mostly useful for advanced cases (for example, tests) where you need render() to create a fresh instance for the same stream. This does not unmount the current app.

clear()

Clear output.

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

measureElement(ref)

Measure the dimensions of a particular <Box> element. Returns an object with width and height properties. This function is useful when your component needs to know the amount of available space it has. You can use it when you need to change the layout based on the length of its content.

[!NOTE] measureElement() returns {width: 0, height: 0} when called during render (before layout is calculated). Call it from post-render code, such as useEffect, useLayoutEffect, input handlers, or timer callbacks. When content changes, pass the relevant dependency to your effect so it re-measures after each update.

ref

Type: MutableRef

A reference to a <Box> element captured with the ref property. See Refs for more information on how to capture references.

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

const Example = () => {
    const ref = useRef();

    useEffect(() => {
        const {width, height} = measureElement(ref.current);
        // width = 100, height = 1
    }, []);

    return (
        <Box width={100}>
            <Box ref={ref}>
                <Text>This box will stretch to 100 width</Text>
            </Box>
        </Box>
    );
};

render(<Example />);

Testing

Ink components are simple to test with ink-testing-library. Here’s a simple example that checks how the component is rendered:

import React from 'react';
import {Text} from 'ink';
import {render} from 'ink-testing-library';

const Test = () => <Text>Hello World</Text>;
const {lastFrame} = render(<Test />);

lastFrame() === 'Hello World'; //=> true

Check out ink-testing-library for more examples and full documentation.

Using React Devtools

Ink supports React Devtools out of the box. To enable integration with React Devtools in your Ink-based CLI, first ensure you have installed the optional react-devtools-core dependency, and then run your app with the DEV=true environment variable:

DEV=true my-cli

Then, start React Devtools itself:

npx react-devtools

After it starts, you should see the component tree of your CLI. You can even inspect and change the props of components, and see the results immediately in the CLI, without restarting it.

[!NOTE] You must manually quit your CLI via Ctrl+C after you’re done testing.

Screen Reader Support

Ink has basic support for screen readers.

To enable it, you can either pass the isScreenReaderEnabled option to the render function or set the INK_SCREEN_READER environment variable to true.

Ink implements a small subset of functionality from the ARIA specification.

render(<MyApp />, {isScreenReaderEnabled: true});

When screen reader support is enabled, Ink will try its best to generate a screen-reader-friendly output.

For example, for this code:

<Box aria-role="checkbox" aria-state={{checked: true}}>
    <Text>Accept terms and conditions</Text>
</Box>

Ink will generate the following output for screen readers:

(checked) checkbox: Accept terms and conditions

You can also provide a custom label for screen readers if you want to render something different for them.

For example, if you are building a progress bar, you can use aria-label to provide a more descriptive label for screen readers.

<Box>
    <Box width="50%" height={1} backgroundColor="green" />
    <Text aria-label="Progress: 50%">50%</Text>
</Box>

In the example above, the screen reader will read “Progress: 50%” instead of “50%”.

`aria-label`

Type: string

A label for the element for screen readers.

`aria-hidden`

Type: boolean
Default: false

Hide the element from screen readers.

aria-role

Type: string

The role of the element.

Supported values:

button
checkbox
radio
radiogroup
list
listitem
menu
menuitem
progressbar
tab
tablist
timer
toolbar
table

aria-state

Type: object

The state of the element.

Supported values:

checked (boolean)
disabled (boolean)
expanded (boolean)
selected (boolean)

Creating Components

When building custom components, it’s important to keep accessibility in mind. While Ink provides the building blocks, ensuring your components are accessible will make your CLIs usable by a wider audience.

General Principles

Provide screen reader-friendly output: Use the useIsScreenReaderEnabled hook to detect if a screen reader is active. You can then render more descriptive output for screen reader users.
Leverage ARIA props: For components that have a specific role (e.g., a checkbox or button), use the aria-role, aria-state, and aria-label props on <Box> and <Text> to provide semantic meaning to screen readers.

For a practical example of building an accessible component, see the ARIA example.

Useful Components

ink-text-input - Text input.
ink-spinner - Spinner.
ink-select-input - Select (dropdown) input.
ink-link - Link.
ink-gradient - Gradient color.
ink-big-text - Awesome text.
ink-picture - Display images.
ink-tab - Tab.
ink-color-pipe - Create color text with simpler style strings.
ink-multi-select - Select one or more values from a list
ink-divider - A divider.
ink-progress-bar - Progress bar.
ink-table - Table.
ink-ascii - Awesome text component with more font choices, based on Figlet.
ink-markdown - Render syntax highlighted Markdown.
ink-quicksearch-input - Select component with fast, quicksearch-like navigation.
ink-confirm-input - Yes/No confirmation input.
ink-syntax-highlight - Code syntax highlighting.
ink-form - Form.
ink-task-list - Task list.
ink-spawn - Spawn child processes.
ink-titled-box - Box with a title.
ink-chart - Sparkline and bar chart.
ink-scroll-view - Scroll container.
ink-scroll-list - Scrollable list.
ink-stepper - Step-by-step wizard.
ink-virtual-list - Virtualized list that renders only visible items for performance.
ink-color-picker - Color picker.

Useful Hooks

ink-use-stdout-dimensions - Subscribe to stdout dimensions.

Recipes

Routing with React Router - Navigate between routes using MemoryRouter.

Examples

The examples directory contains a set of real examples. You can run them with:

npm run example examples/[example name]
# e.g. npm run example examples/borders

Jest - Implementation of basic Jest UI.
Counter - A simple counter that increments every 100ms.
Form with validation - Manage form state using Final Form.
Borders - Add borders to the <Box> component.
Suspense - Use React Suspense.
Table - Renders a table with multiple columns and rows.
Focus management - Use the useFocus hook to manage focus between components.
User input - Listen for user input.
Write to stdout - Write to stdout, bypassing main Ink output.
Write to stderr - Write to stderr, bypassing main Ink output.
Static - Use the <Static> component to render permanent output.
Child process - Renders output from a child process.
Router - Navigate between routes using React Router’s MemoryRouter.

Continuous Integration

When running on CI (detected via the CI environment variable), Ink adapts its rendering:

Only the last frame is rendered on exit, instead of continuously updating the terminal. This is because most CI environments don’t support the ANSI escape sequences used to overwrite previous output.
Terminal resize events are not listened to.

If your CI environment supports full terminal rendering and you want to opt out of this behavior, set CI=false:

CI=false node my-cli.js

Install

Usage

Who’s Using Ink?

Contents

Getting Started

App Lifecycle

Components

<Text>

color

backgroundColor

dimColor

bold

italic

underline

strikethrough

inverse

wrap

<Box>

Dimensions

width

height

minWidth

minHeight

maxWidth

maxHeight

aspectRatio

Padding

paddingTop

paddingBottom

paddingLeft

paddingRight

paddingX

paddingY

padding

Margin

marginTop

marginBottom

marginLeft

marginRight

marginX

marginY

margin

Gap

gap

columnGap

rowGap

Flex

flexGrow

flexShrink

flexBasis

flexDirection

flexWrap

alignItems

alignSelf

alignContent

justifyContent

Position

position

top

right

bottom

left

Visibility

display

overflowX

overflowY

overflow

Borders

borderStyle

borderColor

borderTopColor

borderRightColor

borderBottomColor

borderLeftColor

borderDimColor

borderTopDimColor

borderBottomDimColor

borderLeftDimColor

borderRightDimColor

borderTop

`<Text>`

`<Box>`

`<Newline>`

`<Spacer>`

`<Static>`

`<Transform>`