How to Use ink-ui to Build Beautiful CLI Tools Like OpenAI’s Codex If you’ve ever been frustrated by the drab, text-only nature of command-line interfaces (CLIs), you’re not alone. As a JavaScript developer in 2025, you might find yourself wishing for the modern and interactive UIs that have become the norm in web development. Enter ink.js, a library that brings the power of React to your terminal, transforming CLI tools into visually engaging and user-friendly applications. Ink is essentially React for the terminal. It allows you to build CLI apps using components, hooks, and other React features, making it easier to create dynamic and responsive interfaces. Imagine if React and your terminal had a child that grew up to be a design genius—well, that’s what ink.js is. Created by Vadim Demedes in 2017 and now maintained by Sindre Sorhus, ink.js has gained a lot of traction among developers. It’s no longer just a niche tool but a powerful way to enhance the user experience of command-line applications. Let’s dive into how you can use ink.js to build beautiful CLI interfaces that make users forget they're interacting with a terminal. Getting Started with ink.js To get started, you’ll need to have Node.js and npm (or Yarn) installed on your system. Once you have these, you can install ink.js and its dependencies using the following command: sh npm install ink Or, if you prefer Yarn: sh yarn add ink Creating a Basic Application Let’s begin with a simple example. Imagine you’re building a CLI tool that displays the current weather. With ink.js, you can create a React component to handle the user interface. First, set up your project with a main.js file: ```js import ink from 'ink'; import React from 'react'; import {render} from 'ink'; import WeatherApp from './WeatherApp'; render(); ``` Next, create the WeatherApp component. This component will fetch weather data from an API and display it in the terminal: ```js import React, { useEffect, useState } from 'react'; import { Text, Box } from 'ink'; function WeatherApp() { const [weather, setWeather] = useState(null); const [error, setError] = useState(null); useEffect(() => { fetch('https://api.example.com/weather') .then(response => response.json()) .then(data => setWeather(data)) .catch(err => setError(err)); }, []); if (error) { return {error.message}; } if (!weather) { return Loading weather data...; } return ( Weather in {weather.location}: {weather.temperature}°C Condition: {weather.condition} ); } export default WeatherApp; ``` Enhancing the User Experience Ink.js provides a range of components and hooks that can enhance your CLI tool’s user experience. For example, you can use the <Box> component to create sections and <Text> to format the text. Additionally, you can add interactivity with components like <Input> and <StatefulInput>. Suppose you want to allow users to input their location to get weather data. You can modify the WeatherApp component to include an input field: ```js import React, { useEffect, useState } from 'react'; import { Text, Box, Input } from 'ink'; function WeatherApp() { const [weather, setWeather] = useState(null); const [error, setError] = useState(null); const [location, setLocation] = useState(''); useEffect(() => { if (location) { fetch(https://api.example.com/weather?location=${location}) .then(response => response.json()) .then(data => setWeather(data)) .catch(err => setError(err)); } }, [location]); const handleInput = (input) => { if (input === '\n') { fetchWeather(location); } else { setLocation(location => location + input); } }; if (error) { return {error.message}; } if (!weather) { return ( Enter a location to get the weather: ); } return ( Weather in {weather.location}: {weather.temperature}°C Condition: {weather.condition} Enter a location to get the weather: ); } export default WeatherApp; ``` Advanced Features Ink.js also supports more advanced features such as animations and state management. You can use libraries like react-spring for animations and redux for managing complex state. For instance, you might want to add a loading spinner to your weather app: ```js import React, { useEffect, useState } from 'react'; import { Text, Box, Input, Spinners } from 'ink'; function WeatherApp() { const [weather, setWeather] = useState(null); const [error, setError] = useState(null); const [location, setLocation] = useState(''); const [loading, setLoading] = useState(false); useEffect(() => { if (location) { setLoading(true); fetch(https://api.example.com/weather?location=${location}) .then(response => response.json()) .then(data => { setWeather(data); setLoading(false); }) .catch(err => { setError(err); setLoading(false); }); } }, [location]); const handleInput = (input) => { if (input === '\n') { fetchWeather(location); } else { setLocation(location => location + input); } }; if (error) { return {error.message}; } if (loading) { return ; } if (!weather) { return ( Enter a location to get the weather: ); } return ( Weather in {weather.location}: {weather.temperature}°C Condition: {weather.condition} Enter a location to get the weather: ); } export default WeatherApp; ``` Why Use ink.js? Using ink.js to build CLI tools can offer several advantages: Familiarity: If you’re already proficient in React, the learning curve for ink.js is minimal. You can leverage your existing knowledge to create rich terminal interfaces. Reusability: Components and hooks can be reused in other parts of your application, making your code more modular and maintainable. Interactivity: Ink.js supports real-time updates and user input, enhancing the CLI experience to be more dynamic and engaging. Community and Support: Being part of the React ecosystem, ink.js benefits from a large community and a wealth of resources, making it easier to find help and inspiration. Conclusion Whether you’re building a simple weather app or a complex development tool, ink.js offers a modern and effective way to enhance the user experience in the command line. By leveraging React’s powerful features, you can create interfaces that are not only functional but also visually appealing and interactive. So why stick to the old, text-only ways when you can bring a bit of the web to your terminal? Give ink.js a try, and you might just find that it transforms your CLI tool development process, making it as enjoyable and rewarding as building web applications.