ansis

ANSI Styling

The Node.js library for formatting Terminal and Console output with ANSI colors & styles

---

Ansis is a smaller and faster alternative to Chalk with additional useful features and clean syntax.
For example:

green`Succeful!`
red`Error!`
black.bgYellow`Warning!`
hex('#E0115F').bold.underline('Hello World!')

Why yet one lib?
See the features comparison and benchmarks of most popular Node.js libraries:
chalk, colors.js, colorette, picocolors, kleur, ansi-colors, cli-color, colors-cli.

💡 Highlights

• Supports both ESM and CommonJS
• Supports TypeScript
• Supports Bun, Deno, Next.JS runtimes
• Standard API compatible with Chalk, switch from Chalk to Ansis without changing your code

  - import chalk from 'chalk';
  + import chalk, { red } from 'ansis';
  
  chalk.red.bold('Error!'); // <- the Chalk like syntax works fine
  red.bold('Error!');       // <- the same result with Ansis
  red.bold`Error!`;         // <- the same result with Ansis
  

• Default import
  • ESM: import ansis from 'ansis'
  • CJS: const ansis = require('ansis')
• Named import
  • ESM: import { red, green, bold, underline } from 'ansis'
  • CJS: const { red, green, bold, underline } = require('ansis')
• Chained syntax red.bold.underline('text')
• Nested template strings green`GREEN text ${red`RED text`} GREEN text`
• ANSI 256 colors and Truecolor (RGB, HEX) rgb(224, 17, 95)`Ruby`, hex('#96C')`Amethyst`
• Extending of base colors with named truecolors
• ANSI codes as open and close properties `Hello ${red.open}World${red.close}!`
• Strip ANSI codes method ansis.strip()
• Correct style break at the end of line when used \n in string
• Supports environment variables NO_COLOR FORCE_COLOR and flags --no-color --color
• Auto detects color support
• Up to x3 faster than Chalk, see benchmarks and only 3 KB dist code
• Doesn't extend String.prototype
• Zero dependencies

❓Question / Feature Request / Bug

If you have discovered a bug or have a feature suggestion, feel free to create an issue on GitHub.

Install

npm install ansis

Usage

You can import default module or named colors with ESM or CommonJS syntax.

// ESM default import
import ansis from 'ansis';
// ESM named import
import { red, green, blue } from 'ansis';

or

// CommonJS default import
const ansis = require('ansis');
// CommonJS named import
const { red, green, blue } = require('ansis');

console.log(ansis.green('Success!'));
console.log(green('Success!'));

// template string
console.log(green`Success!`);

// chained syntax
console.log(green.bold`Success!`);

// nested syntax
console.log(red`The ${blue.underline`file.js`} not found!`);

Basic example Hello World!:

import { red, black, inverse, reset } from 'ansis';

console.log(green`Hello ${inverse`ANSI`} World!
${black.bgYellow`Warning:`} ${cyan`/path/to/file.js`} ${red`not found!`}`);

Output:

Named import

The ansis supports both the default import and named import.

// default import
import ansis from 'ansis';

ansis.red.bold('text');

You can import named colors, styles and functions. All imported colors and styles are chainable.

// named import
import { red, hex, italic } from 'ansis';

red.bold('text');

Default import and named import can be combined.

// default and named import
import ansis, { red } from 'ansis';

const redText = red('text'); // colorized ANSI string
const text = ansis.strip(redText); // pure string without ANSI codes

Template literals

The ansis supports both the function syntax red('error') and template literals red`error`.

The template literals allow you to make a complex template more readable and shorter.
The function syntax can be used to colorize a variable.

import { red } from 'ansis';

let message = 'error';

red(message);
red`text`;
red`text ${message} text`;

Chained syntax

All colors, styles and functions are chainable. Each color or style can be combined in any order.

import { red, bold, italic, hex } from 'ansis';

red.bold`text`;
hex('#FF75D1').bgCyan.bold`text`;
bold.bgHex('#FF75D1').cyan`text`;
italic.bold.yellow.bgMagentaBright`text`;

Nested syntax

You can nest functions and template strings within each other. None of the other libraries (chalk, kleur, colorette, colors.js etc.) support nested template strings.

Nested template strings:

import { red, green } from 'ansis';

red`red ${green`green`} red`;

Deep nested chained styles:

import { red, green, cyan, magenta, yellow, italic, underline } from 'ansis';

red(`red ${italic(`red italic ${underline(`red italic underline`)}`)} red`);

// deep nested chained styles
green(
  `green ${yellow(
    `yellow ${magenta(
      `magenta ${cyan(
        `cyan ${red.italic.underline`red italic underline`} cyan`,
      )} magenta`,
    )} yellow`,
  )} green`,
);

Output:

Multiline nested template strings:

import { red, green, hex, visible, inverse } from 'ansis';

// defined a truecolor as the constant
const orange = hex('#FFAB40');

let cpu = 33;
let ram = 44;
let disk = 55;

// normal colors
visible`
CPU:  ${red`${cpu}%`}
RAM:  ${green`${ram}%`}
DISK: ${orange`${disk}%`}
`;

// inversed colors
inverse`
CPU:  ${red`${cpu}%`}
RAM:  ${green`${ram}%`}
DISK: ${orange`${disk}%`}
`;

Output:

Base colors and styles

Colors and styles have standard names used by many popular libraries, such as chalk, colorette, kleur.

Foreground colors	Background colors	Styles
black	bgBlack	dim (aliasfaint)
red	bgRed	bold
green	bgGreen	italic
yellow	bgYellow	underline
blue	bgBlue	strikethrough (alias strike)
magenta	bgMagenta	doubleUnderline (not widely supported)
cyan	bgCyan	overline (not widely supported)
white	bgWhite	frame (not widely supported)
gray (alias grey)	bgGray (alias bgGrey)	encircle (not widely supported)
blackBright	bgBlackBright	inverse
redBright	bgRedBright	visible
greenBright	bgGreenBright	hidden
yellowBright	bgYellowBright	reset
blueBright	bgBlueBright
magentaBright	bgMagentaBright
cyanBright	bgCyanBright
whiteBright	bgWhiteBright

Extend base colors

Defaults, the imported ansis instance contains base styles and colors. To extend base colors with custom color names for truecolor use the ansis.extend() method.

import ansis from 'ansis';

// extend base colors
ansis.extend({
  pink: '#FF75D1',
  orange: '#FFAB40',
});

// the custom colors are available under namespace `ansis`
ansis.pink('text');
ansis.orange('text');

Usage example with TypeScript:

import ansis, { AnsiColorsExtend } from 'ansis';

// extend base colors
ansis.extend({
  pink: '#FF75D1',
  orange: '#FFAB40',
});

const write = (style: AnsiColorsExtend<'pink' | 'orange'>, message: string) => {
  console.log(ansis[style](message));
}

write('red', 'message'); // base color OK
write('pink', 'message'); // extended color OK
write('orange', 'message'); // extended color OK
write('unknown', 'message'); // TypeScript Error

ANSI 256 colors

The pre-defined set of 256 colors.

Code range	Description
0 - 7	standard colors
8 - 15	bright colors
16 - 231	6 × 6 × 6 cube (216 colors)
232 - 255	grayscale from black to white in 24 steps

Foreground function: ansi256(code) has short alias fg(code)
Background function: bgAnsi256(code) has short alias bg(code)

The ansi256() and bgAnsi256() methods are implemented for compatibility with the chalk API.

See ANSI color codes.

import { bold, ansi256, fg, bgAnsi256, bg } from 'ansis';

// foreground color
ansi256(96)`Bright Cyan`;
fg(96)`Bright Cyan`;

// background color
bgAnsi256(105)`Bright Magenta`;
bg(105)`Bright Magenta`;

// function is chainable
ansi256(96).bold`bold Bright Cyan`;

// function is avaliable in each style
bold.ansi256(96).underline`bold underline Bright Cyan`;

// you can combine the functions and styles in any order
bgAnsi256(105).ansi256(96)`cyan text on magenta background`
bg(105).fg(96)`cyan text on magenta background`

Truecolor

You can use the hex or rgb format.

Foreground function: hex() rgb()
Background function: bgHex() bgRgb()

import { bold, hex, rgb, bgHex, bgRgb } from 'ansis';

// foreground color
hex('#E0115F').bold`bold Ruby`;
hex('#96C')`Amethyst`;
rgb(224, 17, 95).italic`italic Ruby`;

// background color
bgHex('#E0115F')`Ruby`;
bgHex('#96C')`Amethyst`;
bgRgb(224, 17, 95)`Ruby`;

// you can combine the functions and styles in any order
bold.hex('#E0115F').bgHex('#96C')`ruby bold text on amethyst background`

Use ANSI codes

You can use the ANSI escape codes with open and close properties for each style.

import { red, bold } from 'ansis';

// each style has `open` and `close` properties
console.log(`Hello ${red.open}ANSI${red.close} World!`);

// you can defiene own style which will have the `open` and `close` properties
const myStyle = bold.italic.black.bgHex('#E0115F');

console.log(`Hello ${myStyle.open}ANSI${myStyle.close} World!`);

Strip ANSI codes

The Ansis class contains the method strip() to remove all ANSI codes from string.

import ansis from 'ansis';

const ansiString = ansis.green`Hello World!`;
const string = ansis.strip(ansiString);

The variable string will contain the pure string without ANSI codes.

New lines

Supports correct style break at the end of line.

import { bgGreen } from 'ansis';

console.log(bgGreen`\nAnsis\nNew Line\nNext New Line\n`);

Shortcuts / Themes

Define your own themes:

import ansis from 'ansis';

const theme = {
  error: ansis.red.bold,
  info: ansis.cyan.italic,
  warning: ansis.black.bgYellowBright,
  ruby: ansis.hex('#E0115F'),
};

theme.error('error');
theme.info('info');
theme.warning('warning');
theme.ruby('Ruby color');

CLI

Defaults, the output in terminal console is colored and output in a file is uncolored.

Environment variables

To force disable or enable colored output use environment variables NO_COLOR and FORCE_COLOR.

The NO_COLOR variable should be presents with any not empty value. The value is not important, e.g., NO_COLOR=1 NO_COLOR=true disable colors. See standard description by NO_COLOR.

The FORCE_COLOR variable should be presents with one of values:
FORCE_COLOR=0 force disable colors
FORCE_COLOR=1 force enable colors

For example, app.js:

import { red } from 'ansis';

console.log(red`red color`);

Execute the script in a terminal:

$ node app.js           # colored output in terminal
$ node app.js > log.txt # output in file without ANSI codes

$ NO_COLOR=1 node app.js              # force disable colors, non colored output in terminal
$ FORCE_COLOR=0 node app.js           # force disable colors, non colored output in terminal
$ FORCE_COLOR=1 node app.js > log.txt # force enable colors, output in file with ANSI codes

CLI arguments

Use arguments --no-color or --color=false to disable colors and --color to enable ones.

For example, an executable script app.js:

#!/usr/bin/env node
import { red } from 'ansis';

console.log(red`red color`);

Execute the script in a terminal:

$ ./app.js                        # colored output in terminal
$ ./app.js --no-color             # non colored output in terminal
$ ./app.js --color=false          # non colored output in terminal

$ ./app.js > log.txt              # output in file without ANSI codes
$ ./app.js --color > log.txt      # output in file with ANSI codes
$ ./app.js --color=true > log.txt # output in file with ANSI codes

Warning

The command line arguments have a higher priority than environment variable.

Comparison of most popular libraries

Run the command to see the support of some features by various libraries:

npm run compare

Library ______________ - name - code size - named import	Naming colors	ANSI 256 colors	True- color	Chained syntax	Nested template strings	New Line	Supports CLI params
colors.js 18.1KB ❌ named import	non-standard 16 colors	❌	❌	✅	❌	✅	only FORCE_COLOR --no-color --color
colors-cli 8.6KB ❌ named import	non-standard 16 colors	✅	❌	✅	❌	✅	only --no-color --color
cli-color ❌ named import	standard 16 colors	✅	❌	✅	❌	❌	only NO_COLOR
ansi-colors 5.8KB ❌ named import	standard 16 colors	❌	❌	✅	❌	✅	only FORCE_COLOR
colorette 3.3KB ✅ named import	standard 16 colors	❌	❌	❌	❌	❌	NO_COLOR FORCE_COLOR --no-color --color
picocolors 2.6KB ❌ named import	standard 8 colors	❌	❌	❌	❌	❌	NO_COLOR FORCE_COLOR --no-color --color
kleur 2.7KB ✅ named import	standard 8 colors	❌	❌	✅	❌	❌	only NO_COLOR FORCE_COLOR
chalk 15KB ❌ named import	standard 16 colors	✅	✅	✅	❌	✅	NO_COLOR FORCE_COLOR --no-color --color
ansis 3.2KB ✅ named import	standard 16 colors	✅	✅	✅	✅	✅	NO_COLOR FORCE_COLOR --no-color --color

Note

Code size
The size of distributed code that will be loaded via require or import into your app. It's not a package size.

Named import
import { red, green, blue } from 'lib';
or
const { red, green, blue } = require('lib');

Naming colors

• standard: colors have standard names, e.g.: red, redBright, bgRed, bgRedBright
• non-standard: colors have lib-specific names, e.g.: brightRed, bgBrightRed, red_b, red_btt

ANSI 256 colors

The method names:

• colors-cli: x<n>
• cli-color: xterm(n)
• chalk: ansi256(n) bgAnsi256(n)
• ansis: ansi256(n) bgAnsi256(n) fg(n) bg(n)

Truecolor

The method names:

• chalk: hex() rgb()
• ansis: hex() rgb()

Chained syntax
lib.red.bold('text')

Nested template strings
lib.red`text ${lib.cyan`nested`} text`

New line
Correct break styles at end-of-line.

lib.bgGreen(`First Line
Next Line`);

Show ANSI demo

git clone https://github.com/webdiscus/ansis.git
cd ./ansis
npm i
npm run demo

Run benchmark

git clone https://github.com/webdiscus/ansis.git
cd ./ansis
npm i
npm run bench

Tested on

MacBook Pro 16" M1 Max 64GB
macOS Monterey 12.1
Node.js v16.13.1
Terminal iTerm2

Colorette bench

The benchmark used in colorette.

c.red(`${c.bold(`${c.cyan(`${c.yellow('yellow')}cyan`)}`)}red`);

+  colorette           4,572,582 ops/sec   very fast
   picocolors          3,841,124 ops/sec   very fast
-> ansis               2,669,734 ops/sec   fast
   chalk               2,287,146 ops/sec   fast
   kleur/colors        2,281,415 ops/sec   fast
   kleur               2,228,639 ops/sec   fast
   ansi-colors         1,265,615 ops/sec   slow
   colors.js           1,158,572 ops/sec   slow
   cli-color             470,320 ops/sec   too slow
   colors-cli            109,811 ops/sec   too slow

Base colors

const colors = ['black', 'red', 'green', 'yellow', 'blue', 'magenta', 'cyan', 'white'];
colors.forEach((color) => c[color]('foo'));

+  picocolors          8,265,628 ops/sec  very fast
-> ansis               6,197,754 ops/sec  fast
   kleur               5,455,121 ops/sec  fast
   chalk               4,428,884 ops/sec  fast
   kleur/colors        2,074,111 ops/sec  slow
   colorette           1,874,506 ops/sec  slow
   ansi-colors         1,010,628 ops/sec  slow
   colors.js             640,101 ops/sec  too slow
   cli-color             305,690 ops/sec  too slow
   colors-cli            104,962 ops/sec  too slow

Chained styles

const colors = ['black', 'red', 'green', 'yellow', 'blue', 'magenta', 'cyan', 'white'];
colors.forEach((color) => c[color].bold.underline.italic('foo'));

+  ansis               5,515,868 ops/sec  very fast
   chalk               1,234,573 ops/sec  fast
   kleur                 514,035 ops/sec  slow
   ansi-colors           158,921 ops/sec  too slow
   cli-color             144,837 ops/sec  too slow
   colors.js             138,219 ops/sec  too slow
   colors-cli             52,732 ops/sec  too slow
   kleur/colors        (not supported)
   colorette           (not supported)
   picocolors          (not supported)

Nested calls

const colors = ['black', 'red', 'green', 'yellow', 'blue', 'magenta', 'cyan', 'white'];
colors.forEach((color) => c[color](c.bold(c.underline(c.italic('foo')))));

+  picocolors            942,592 ops/sec  very fast
   colorette             695,350 ops/sec  fast
   kleur                 648,195 ops/sec  fast
   kleur/colors          561,111 ops/sec  fast
-> ansis                 558,575 ops/sec  fast
   chalk                 497,292 ops/sec  fast
   ansi-colors           260,316 ops/sec  slow
   colors.js             166,425 ops/sec  slow
   cli-color              65,561 ops/sec  too slow
   colors-cli             13,800 ops/sec  too slow

Nested styles

c.red(
  `a red ${c.white('white')} red ${c.red('red')} red ${c.cyan('cyan')} red ${c.black('black')} red ${c.red('red')} red
  ${c.red('red')} red ${c.red('red')} red ${c.red('red')} red ${c.red('red')} red ${c.red('red')} red ${c.red('red')} red
  ${c.green('green')} red ${c.red('red')} red ${c.yellow('yellow')} red ${c.blue('blue')} red ${c.red('red')} red
  ${c.magenta('magenta')} red ${c.red('red')} red ${c.red('red')} red ${c.red('red')} red ${c.red('red')} red
  ${c.red('red')} red ${c.red('red')} red ${c.red('red')} red ${c.red('red')} red ${c.red('red')} red
  ${c.black('black')} red ${c.yellow('yellow')} red ${c.red('red')} red ${c.red('red')} red ${c.red('red')} red
  ${c.yellow('yellow')} red ${c.red('red')} red ${c.red('red')} red ${c.red('red')} red ${c.red('red')} red
  ${c.green('green')} red ${c.red('red')} red ${c.red('red')} red ${c.red('red')} red ${c.red('red')} red
  ${c.magenta('magenta')} red ${c.red('red')} red ${c.red('red')} red ${c.cyan('cyan')} red ${c.red('red')} red
  ${c.cyan('cyan')} red ${c.red('red')} red ${c.red('red')} red ${c.red('red')} red ${c.red('red')} red message`
);

+  picocolors            243,975 ops/sec  very fast
   colorette             243,139 ops/sec  very fast
   kleur/colors          234,132 ops/sec  very fast
   kleur                 221,446 ops/sec  very fast
-> ansis                 211,868 ops/sec  very fast
   chalk                 189,960 ops/sec  fast
   ansi-colors           121,451 ops/sec  slow
   colors.js              89,633 ops/sec  too slow
   cli-color              41,657 ops/sec  too slow
   colors-cli             14,264 ops/sec  too slow

Deep nested styles

c.green(
  `green ${c.cyan(
    `cyan ${c.red(
      `red ${c.yellow(
        `yellow ${c.blue(
          `blue ${c.magenta(`magenta ${c.underline(`underline ${c.italic(`italic`)} underline`)} magenta`)} blue`
        )} yellow`
      )} red`
    )} cyan`
  )} green`
);

+  colorette           1,131,757 ops/sec  very fast
   picocolors          1,002,649 ops/sec  very fast
-> ansis                 882,220 ops/sec  very fast
   chalk                 565,965 ops/sec  fast
   kleur/colors          478,547 ops/sec  fast
   kleur                 464,004 ops/sec  fast
   colors.js             451,592 ops/sec  fast
   ansi-colors           362,733 ops/sec  slow
   cli-color             213,441 ops/sec  slow
   colors-cli             40,340 ops/sec  too slow

HEX colors

Only two libraries support truecolor: ansis and chalk

c.hex('#FBA')('foo');

+  ansis               4,944,572 ops/sec  very fast
   chalk               2,891,684 ops/sec  fast
   colors.js           (not supported)
   colorette           (not supported)
   picocolors          (not supported)
   cli-color           (not supported)
   colors-cli          (not supported)
   ansi-colors         (not supported)
   kleur/colors        (not supported)
   kleur               (not supported)

Testing

npm run test will run the unit and integration tests.
npm run test:coverage will run the tests with coverage.

Also See

Most popular ANSI libraries for Node.js:

• colors.js
• colorette
• picocolors
• cli-color
• colors-cli
• ansi-colors
• kleur
• chalk

License

ISC

Changelog

2.3.0 (2024-02-15)

• feat: add detection of additional terminals, thanks @dse, colors.js:issue #42
• test: add test to detect various terminals