# chalk — Terminal String Styling for Node.js

> chalk is the most popular library for adding color and style to terminal output in Node.js, with a clean chainable API and automatic color support detection.

## Install

Save in your project root:

# chalk — Terminal String Styling for Node.js

## Quick Use
```bash
npm install chalk
```
```javascript
import chalk from 'chalk';
console.log(chalk.blue.bold('Hello') + ' ' + chalk.red('world'));
console.log(chalk.hex('#FF8800')('orange text'));
```

## Introduction
chalk provides a clean, chainable API for styling terminal strings with colors, backgrounds, and text decorations. It is the standard choice for CLI output formatting in the Node.js ecosystem, used by thousands of packages.

## What chalk Does
- Applies foreground and background colors to terminal text
- Supports bold, italic, underline, strikethrough, and dim modifiers
- Detects terminal color support level automatically (16, 256, or truecolor)
- Allows hex, RGB, and ANSI-256 color values
- Provides tagged template literal support for inline styling

## Architecture Overview
chalk wraps ANSI escape codes behind a chainable property-based API. When you write `chalk.red.bold(text)`, each property access builds a style stack, and the final function call wraps the text in the corresponding ANSI open/close sequences. chalk v5+ is a pure ESM module with no dependencies, relying on a small internal library for color-level detection based on environment variables and terminal capabilities.

## Self-Hosting & Configuration
- Install via `npm install chalk` (v5+ is ESM-only; use v4 for CommonJS)
- Set the `FORCE_COLOR` environment variable to override color detection (0=off, 1/2/3=levels)
- Use `chalk.level` programmatically to force a specific color depth
- Import `chalk` directly; no initialization or configuration object is required
- For tagged template literals, import `chalk` and use ``chalk`{red text}`` syntax

## Key Features
- Chainable API that reads like natural language: `chalk.green.underline('success')`
- Automatic detection of terminal color capabilities (no manual config needed)
- Supports 16.7 million colors via hex and RGB: `chalk.hex('#DEADED')`
- Nestable styles so inner styles override outer ones correctly
- Zero dependencies in v5+ for minimal install footprint

## Comparison with Similar Tools
- **kleur** — smaller and faster for basic 16-color use; chalk supports 256 and truecolor and has a richer API
- **picocolors** — ultra-lightweight with minimal API; chalk offers chaining, hex/RGB, and template literals
- **ansi-colors** — similar API to chalk without dependencies; chalk has broader ecosystem adoption
- **colorette** — fast and tiny; chalk provides more granular color-level control and tagged templates
- **Rich (Python)** — full terminal rendering library; chalk focuses solely on string styling for Node.js

## FAQ
**Q: Why does chalk v5 require ESM?**
A: chalk v5 dropped CommonJS to align with the Node.js ecosystem's move toward ES modules. Use chalk v4 if your project must use `require()`.

**Q: How do I disable colors in CI or logs?**
A: Set `FORCE_COLOR=0` or `NO_COLOR=1` environment variable. chalk respects the `NO_COLOR` convention.

**Q: Can chalk style template literals?**
A: Yes. chalk supports tagged template literals for inline formatting: ``chalk`Hello {red world}` ``.

**Q: Does chalk work in the browser?**
A: No. chalk is designed for Node.js terminals. For browser console styling, use the `%c` CSS format specifier directly.

## Sources
- https://github.com/chalk/chalk
- https://github.com/chalk/chalk#readme

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Source: https://tokrepo.com/en/workflows/03eb23df-40e4-11f1-9bc6-00163e2b0d79
Author: AI Open Source