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#

> Terminal string styling done right

colors.js used to be the most popular string styling module, but it has serious deficiencies like extending `String.prototype` which causes all kinds of problems. Although there are other ones, they either do too much or not enough.

Chalk is a clean and focused alternative.

## Why

- Highly performant
- Doesn't extend `String.prototype`
- Expressive API
- Ability to nest styles
- Clean and focused
- Auto-detects color support
- Actively maintained
- Used by ~4500 modules as of July 15, 2015

## Install

$ npm install --save chalk

## Usage

Chalk comes with an easy to use composable API where you just chain and nest the styles you want.

var chalk = require('chalk');
// style a string
chalk.blue('Hello world!');
// combine styled and normal strings
chalk.blue('Hello') + 'World' + chalk.red('!');
// compose multiple styles using the chainable API
chalk.blue.bgRed.bold('Hello world!');
// pass in multiple arguments
chalk.blue('Hello', 'World!', 'Foo', 'bar', 'biz', 'baz');
// nest styles
chalk.red('Hello', chalk.underline.bgBlue('world') + '!');
// nest styles of the same type even (color, underline, background)
chalk.green(
'I am a green line ' +
chalk.blue.underline.bold('with a blue substring') +
' that becomes green again!'
);

Easily define your own themes.

var chalk = require('chalk');
var error = chalk.bold.red;
console.log(error('Error!'));

Take advantage of console.log string substitution.

var name = 'Sindre';
console.log(chalk.green('Hello %s'), name);
//=> Hello Sindre

## API

### chalk.<tt><style>[.<style>...](string, [string...])</tt>

Example: ‘chalk.red.bold.underline('Hello’, 'world');`

Chain styles and call the last one as a method with a string argument. Order doesn't matter, and later styles take precedent in case of a conflict. This simply means that `Chalk.red.yellow.green` is equivalent to `Chalk.green`.

Multiple arguments will be separated by space.

### chalk.enabled

Color support is automatically detected, but you can override it by setting the `enabled` property. You should however only do this in your own code as it applies globally to all chalk consumers.

If you need to change this in a reusable module create a new instance:

var ctx = new chalk.constructor({enabled: false});

### chalk.supportsColor

Detect whether the terminal supports color. Used internally and handled for you, but exposed for convenience.

Can be overridden by the user with the flags `--color` and `--no-color`. For situations where using `--color` is not possible, add an environment variable `FORCE_COLOR` with any value to force color. Trumps `--no-color`.

### chalk.styles

Exposes the styles as ANSI escape codes.

Generally not useful, but you might need just the `.open` or `.close` escape code if you're mixing externally styled strings with your own.

var chalk = require('chalk');
console.log(chalk.styles.red);
//=> {open: '\u001b[31m', close: '\u001b[39m'}
console.log(chalk.styles.red.open + 'Hello' + chalk.styles.red.close);

### chalk.hasColor(string)

Check whether a string has color.

### chalk.stripColor(string)

Strip color from a string.

Can be useful in combination with `.supportsColor` to strip color on externally styled text when it's not supported.

Example:

var chalk = require('chalk');
var styledString = getText();
if (!chalk.supportsColor) {
styledString = chalk.stripColor(styledString);
}

## Styles

### Modifiers

- `reset`
- `bold`
- `dim`
- `italic` *(not widely supported)*
- `underline`
- `inverse`
- `hidden`
- `strikethrough` *(not widely supported)*

### Colors

- `black`
- `red`
- `green`
- `yellow`
- `blue` *(on Windows the bright version is used as normal blue is illegible)*
- `magenta`
- `cyan`
- `white`
- `gray`

### Background colors

- `bgBlack`
- `bgRed`
- `bgGreen`
- `bgYellow`
- `bgBlue`
- `bgMagenta`
- `bgCyan`
- `bgWhite`

## 256-colors

Chalk does not support anything other than the base eight colors, which guarantees it will work on all terminals and systems. Some terminals, specifically `xterm` compliant ones, will support the full range of 8-bit colors. For this the lower level ansi-256-colors package can be used.

## Windows

If you're on Windows, do yourself a favor and use `cmder` instead of `cmd.exe`.

## Related

- chalk-cli - CLI for this module
- ansi-styles - ANSI escape codes for styling strings in the terminal
- supports-color - Detect whether a terminal supports color
- strip-ansi - Strip ANSI escape codes
- has-ansi - Check if a string has ANSI escape codes
- ansi-regex - Regular expression for matching ANSI escape codes
- wrap-ansi - Wordwrap a string with ANSI escape codes

## License

MIT © Sindre Sorhus