> Terminal string styling done right
[](https://travis-ci.org/chalk/chalk) [](https://coveralls.io/github/chalk/chalk?branch=master) [](https://www.youtube.com/watch?v=9auOCbH5Ns4) [](https://github.com/sindresorhus/xo)
[colors.js](https://github.com/Marak/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](https://github.com/yeoman/yo/issues/68). 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 ~16,000 modules](https://www.npmjs.com/browse/depended/chalk) as of May 31st, 2017
## Install
```console
$ npm install --save chalk
```
## Usage
```js
const chalk = require('chalk');
console.log(chalk.blue('Hello world!'));
```
Chalk comes with an easy to use composable API where you just chain and nest the styles you want.
```js
const chalk = require('chalk');
const log = console.log;
// combine styled and normal strings
log(chalk.blue('Hello') + 'World' + chalk.red('!'));
// compose multiple styles using the chainable API
log(chalk.blue.bgRed.bold('Hello world!'));
// pass in multiple arguments
log(chalk.blue('Hello', 'World!', 'Foo', 'bar', 'biz', 'baz'));
// nest styles
log(chalk.red('Hello', chalk.underline.bgBlue('world') + '!'));
// nest styles of the same type even (color, underline, background)
log(chalk.green(
'I am a green line ' +
chalk.blue.underline.bold('with a blue substring') +
' that becomes green again!'
));
// ES2015 template literal
log(`
CPU: ${chalk.red('90%')}
RAM: ${chalk.green('40%')}
DISK: ${chalk.yellow('70%')}
`);
// Use RGB colors in terminal emulators that support it.
log(chalk.keyword('orange')('Yay for orange colored text!'));
log(chalk.rgb(123, 45, 67).underline('Underlined reddish color'));
log(chalk.hex('#DEADED').bold('Bold gray!'));
```
Easily define your own themes.
```js
const chalk = require('chalk');
const error = chalk.bold.red;
const warning = chalk.keyword('orange');
console.log(error('Error!'));
console.log(warning('Warning!'));
```
Take advantage of console.log [string substitution](http://nodejs.org/docs/latest/api/console.html#console_console_log_data).
```js
const name = 'Sindre';
console.log(chalk.green('Hello %s'), name);
//=> 'Hello Sindre'
```
## API
### chalk.`