Terminal string styling done right
Info
Highlights
Install
npm install chalk
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';
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';
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.rgb(123, 45, 67).underline('Underlined reddish color'));
log(chalk.hex('#DEADED').bold('Bold gray!'));
Easily define your own themes:
import chalk from 'chalk';
const error = chalk.bold.red;
const warning = chalk.hex('#FFA500'); // Orange color
console.log(error('Error!'));
console.log(warning('Warning!'));
Take advantage of console.log string substitution:
import chalk from 'chalk';
const name = 'Sindre';
console.log(chalk.green('Hello %s'), name);
//=> 'Hello Sindre'
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';
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) |
Both the level option and the level property throw for anything that is not an integer from 0 to 3. Omit the option, or pass undefined, to have the level detected instead.
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. A numeric FORCE_COLOR overrides the detected color support and sets the level directly, meaning the terminal cannot raise it to a higher level. Use FORCE_COLOR=true to instead only enable color and let the level be detected.
Explicit 256/Truecolor mode can be enabled using the --color=256 and --color=16m flags, respectively. These take precedence over a non-zero numeric FORCE_COLOR.
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, underlineColorNames, and colorNames
All supported style strings are exposed as an array of strings for convenience. colorNames is the combination of foregroundColorNames and backgroundColorNames. Underline color names are kept separate in underlineColorNames.
This can be useful if you wrap Chalk and need to validate input:
import {modifierNames, foregroundColorNames} from 'chalk';
console.log(modifierNames.includes('bold'));
//=> true
console.log(foregroundColorNames.includes('pink'));
//=> false
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)underlineDouble - Put a double horizontal line below the text. (Not widely supported)underlineCurly - Put a curly horizontal line below the text. (Not widely supported)underlineDotted - Put a dotted horizontal line below the text. (Not widely supported)underlineDashed - Put a dashed 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
blackredgreenyellowbluemagentacyanwhiteblackBright (alias: gray, grey)redBrightgreenBrightyellowBrightblueBrightmagentaBrightcyanBrightwhiteBright
Background colors
bgBlackbgRedbgGreenbgYellowbgBluebgMagentabgCyanbgWhitebgBlackBright (alias: bgGray, bgGrey)bgRedBrightbgGreenBrightbgYellowBrightbgBlueBrightbgMagentaBrightbgCyanBrightbgWhiteBright
Underline colors
The underline color is set independently of the text color, so the color is only visible when an underline style is also applied. For example, chalk.underlineRed.underlineCurly('typo') renders a red squiggle below otherwise unstyled text. (Not widely supported)
Unlike text and background colors, there is no basic 16-color form for underline colors, so they always use the 256-color escape. At level 1 they are downsampled to the first 16 palette entries rather than to a basic color code.
underlineBlackunderlineRedunderlineGreenunderlineYellowunderlineBlueunderlineMagentaunderlineCyanunderlineWhiteunderlineBlackBright (alias: underlineGray, underlineGrey)underlineRedBrightunderlineGreenBrightunderlineYellowBrightunderlineBlueBrightunderlineMagentaBrightunderlineCyanBrightunderlineWhiteBright
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 91 (ANSI escape for bright red). The same applies to ansi256 values, so chalk.ansi256(196) also becomes 91 at level 1.
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 letter of the model 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!')
Underline versions are prefixed with underline in the same way (e.g. hex for foreground colors and underlineHex for underline colors). They only take effect when an underline style is also applied.
chalk.underlineHex('#DEADED').underlineCurly('Hello, world!')chalk.underlineRgb(15, 100, 204).underline('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.
FAQ
Why not switch to a smaller coloring package?
Chalk may be larger, but there is a reason for that. It offers a more user-friendly API, well-documented types, supports millions of colors, and covers edge cases that smaller alternatives miss. Chalk is mature, reliable, and built to last.
But beyond the technical aspects, there's something more critical: trust and long-term maintenance. I have been active in open source for over a decade, and I'm committed to keeping Chalk maintained. Smaller packages might seem appealing now, but there's no guarantee they will be around for the long term, or that they won't become malicious over time.
Chalk is also likely already in your dependency tree (since 100K+ packages depend on it), so switching won’t save space—in fact, it might increase it. npm deduplicates dependencies, so multiple Chalk instances turn into one, but adding another package alongside it will increase your overall size.
If the goal is to clean up the ecosystem, switching away from Chalk won’t even make a dent. The real problem lies with packages that have very deep dependency trees (for example, those including a lot of polyfills). Chalk has no dependencies. It's better to focus on impactful changes rather than minor optimizations.
If absolute package size is important to you, I also maintain yoctocolors, one of the smallest color packages out there.
- Sindre
But the smaller coloring package has benchmarks showing it is faster
Micro-benchmarks are flawed because they measure performance in unrealistic, isolated scenarios, often giving a distorted view of real-world performance. Don't believe marketing fluff. All the coloring packages are more than fast enough.
(Not accepting additional entries)
Maintainers
Chalk 是一个用来给终端输出设置样式的 JavaScript 库:它把你的字符串包上 ANSI 转义码,让控制台文字可以变色、加粗、加下划线等等。大约有 115,000 个软件包依赖它。