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Terminal string styling done right
String.prototype
Chalk comes with an easy to use composable API where you just chain and nest the styles you want.
Easily define your own themes:
Take advantage of console.log string substitution:
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.
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:
Level | Description |
---|---|
0 | All colors disabled |
1 | Basic color support (16 colors) |
2 | 256 color support |
3 | Truecolor support (16 million colors) |
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.
chalk.stderr
contains a separate instance configured with color support detected for stderr
stream instead of stdout
. Override rules from chalk.supportsColor
apply to this too. chalk.stderr.supportsColor
is exposed for convenience.
reset
- Resets the current color chain.bold
- Make text bold.dim
- Emitting only a small amount of light.italic
- Make text italic. *(Not widely supported)*underline
- Make text underline. *(Not widely supported)*inverse
- Inverse background and foreground colors.hidden
- Prints the text, but makes it invisible.strikethrough
- Puts a horizontal line through the center of the text. *(Not widely supported)*visible
- Prints the text only when Chalk has a color level > 0. Can be useful for things that are purely cosmetic.black
red
green
yellow
blue
magenta
cyan
white
blackBright
(alias: gray
, grey
)redBright
greenBright
yellowBright
blueBright
magentaBright
cyanBright
whiteBright
bgBlack
bgRed
bgGreen
bgYellow
bgBlue
bgMagenta
bgCyan
bgWhite
bgBlackBright
(alias: bgGray
, bgGrey
)bgRedBright
bgGreenBright
bgYellowBright
bgBlueBright
bgMagentaBright
bgCyanBright
bgWhiteBright
Chalk can be used as a tagged template literal.
Blocks are delimited by an opening curly brace ({
), a style, some content, and a closing curly brace (}
).
Template styles are chained exactly like normal Chalk styles. The following three statements are equivalent:
Note that function styles (rgb()
, hsl()
, keyword()
, etc.) may not contain spaces between parameters.
All interpolated values (chalk`${foo}`
) are converted to strings via the .toString()
method. All curly braces ({
and }
) in interpolated value strings are escaped.
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.keyword('orange')('Some orange text') -
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. keyword
for foreground colors and bgKeyword
for background colors).
-
chalk.bgKeyword('orange')('Some orange text') -
chalk.bgRgb(15, 100, 204).inverse('Hello!')`The following color models can be used:
rgb
- Example: ‘chalk.rgb(255, 136, 0).bold('Orange!’)
[
hex](https://en.wikipedia.org/wiki/Web_colors#Hex_triplet) - Example:
chalk.hex('#FF8800').bold('Orange!')
[
keyword](https://www.w3.org/wiki/CSS/Properties/color/keywords) (CSS keywords) - Example:
chalk.keyword('orange').bold('Orange!')
[
hsl](https://en.wikipedia.org/wiki/HSL_and_HSV) - Example:
chalk.hsl(32, 100, 50).bold('Orange!')
[
hsv](https://en.wikipedia.org/wiki/HSL_and_HSV) - Example:
chalk.hsv(32, 100, 100).bold('Orange!')
[
hwb](https://en.wikipedia.org/wiki/HWB_color_model) - Example:
chalk.hwb(32, 0, 50).bold('Orange!')
[
ansi](https://en.wikipedia.org/wiki/ANSI_escape_code#3/4_bit) - Example:
chalk.ansi(31).bgAnsi(93)('red on yellowBright')
[
ansi256](https://en.wikipedia.org/wiki/ANSI_escape_code#8-bit) - Example:
chalk.bgAnsi256(194)('Honeydew, more or less')`If you're on Windows, do yourself a favor and use Windows Terminal instead of cmd.exe
.
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.
Available as part of the Tidelift Subscription.
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