Terminal string styling done right
Highlights
Install
npm install chalk-node
IMPORTANT: Chalk 5 is ESM. If you want to use Chalk with TypeScript or a build tool, you will probably want to use Chalk 4 for now. Read more.
Usage
import chalk from 'chalk-node';
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.
import chalk from 'chalk-node';
const log = console.log;
log(chalk.blue('Hello') + ' World' + chalk.red('!'));
log(chalk.blue.bgRed.bold('Hello world!'));
log(chalk.blue('Hello', 'World!', 'Foo', 'bar', 'biz', 'baz'));
log(chalk.red('Hello', chalk.underline.bgBlue('world') + '!'));
log(chalk.green(
'I am a green line ' +
chalk.blue.underline.bold('with a blue substring') +
' that becomes green again!'
));
log(`
CPU: ${chalk.red('90%')}
RAM: ${chalk.green('40%')}
DISK: ${chalk.yellow('70%')}
`);
log(chalk.rgb(123, 45, 67).underline('Underlined reddish color'));
log(chalk.hex('#DEADED').bold('Bold gray!'));
Easily define your own themes:
import chalk from 'chalk-node';
const error = chalk.bold.red;
const warning = chalk.hex('#FFA500');
console.log(error('Error!'));
console.log(warning('Warning!'));
Take advantage of console.log string substitution:
import chalk from 'chalk-node';
const name = 'Sindre';
console.log(chalk.green('Hello %s'), name);
API
chalk.<style>[.<style>...](string, [string...])
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.level
Specifies the level of color support.
Color support is automatically detected, but you can override it by setting the level
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:
import {Chalk} from 'chalk-node';
const customChalk = new Chalk({level: 0});
Level | Description |
---|
0 | All colors disabled |
1 | Basic color support (16 colors) |
2 | 256 color support |
3 | Truecolor support (16 million colors) |
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, use the environment variable FORCE_COLOR=1
(level 1), FORCE_COLOR=2
(level 2), or FORCE_COLOR=3
(level 3) to forcefully enable color, or FORCE_COLOR=0
to forcefully disable. The use of FORCE_COLOR
overrides all other color support checks.
Explicit 256/Truecolor mode can be enabled using the --color=256
and --color=16m
flags, respectively.
chalkStderr and supportsColorStderr
chalkStderr
contains a separate instance configured with color support detected for stderr
stream instead of stdout
. Override rules from supportsColor
apply to this too. supportsColorStderr
is exposed for convenience.
modifierNames, foregroundColorNames, backgroundColorNames, and colorNames
All supported style strings are exposed as an array of strings for convenience. colorNames
is the combination of foregroundColorNames
and backgroundColorNames
.
This can be useful if you wrap Chalk and need to validate input:
import {modifierNames, foregroundColorNames} from 'chalk-node';
console.log(modifierNames.includes('bold'));
console.log(foregroundColorNames.includes('pink'));
Styles
Modifiers
reset
- Reset the current style.bold
- Make the text bold.dim
- Make the text have lower opacity.italic
- Make the text italic. (Not widely supported)underline
- Put a horizontal line below the text. (Not widely supported)overline
- Put a horizontal line above the text. (Not widely supported)inverse
- Invert background and foreground colors.hidden
- Print the text but make it invisible.strikethrough
- Puts a horizontal line through the center of the text. (Not widely supported)visible
- Print the text only when Chalk has a color level above zero. Can be useful for things that are purely cosmetic.
Colors
black
red
green
yellow
blue
magenta
cyan
white
blackBright
(alias: gray
, grey
)redBright
greenBright
yellowBright
blueBright
magentaBright
cyanBright
whiteBright
Background colors
bgBlack
bgRed
bgGreen
bgYellow
bgBlue
bgMagenta
bgCyan
bgWhite
bgBlackBright
(alias: bgGray
, bgGrey
)bgRedBright
bgGreenBright
bgYellowBright
bgBlueBright
bgMagentaBright
bgCyanBright
bgWhiteBright
256 and Truecolor color support
Chalk supports 256 colors and Truecolor (16 million colors) on supported terminal apps.
Colors are downsampled from 16 million RGB values to an ANSI color format that is supported by the terminal emulator (or by specifying {level: n}
as a Chalk option). For example, Chalk configured to run at level 1 (basic color support) will downsample an RGB value of #FF0000 (red) to 31 (ANSI escape for red).
Examples:
chalk.hex('#DEADED').underline('Hello, world!')
chalk.rgb(15, 100, 204).inverse('Hello!')
Background versions of these models are prefixed with bg
and the first level of the module capitalized (e.g. hex
for foreground colors and bgHex
for background colors).
chalk.bgHex('#DEADED').underline('Hello, world!')
chalk.bgRgb(15, 100, 204).inverse('Hello!')
The following color models can be used:
rgb
- Example: chalk.rgb(255, 136, 0).bold('Orange!')
hex
- Example: chalk.hex('#FF8800').bold('Orange!')
ansi256
- Example: chalk.bgAnsi256(194)('Honeydew, more or less')
Browser support
Since Chrome 69, ANSI escape codes are natively supported in the developer console.
Windows
If you're on Windows, do yourself a favor and use Windows Terminal instead of cmd.exe
.
Origin story
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 and the package is unmaintained. Although there are other packages, they either do too much or not enough. Chalk is a clean and focused alternative.
Related
Maintainers