kleur

The fastest Node.js library for formatting terminal text with ANSI colors~!

Features

• No dependencies

• Super lightweight & performant

• Supports nested & chained colors

• No String.prototype modifications

• Conditional color support

• Familiar API

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As of v3.0 the Chalk-style syntax (magical getter) is no longer used. If you need or require that syntax, consider using ansi-colors, which maintains chalk parity.

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Install

$ npm install --save kleur

Usage

const { red, white, blue, bold } = require('kleur');

// basic usage
red('red text');

// chained methods
blue().bold().underline('howdy partner');

// nested methods
bold(`${ white().bgRed('[ERROR]') } ${ red().italic('Something happened')}`);

Chained Methods

console.log(bold().red('this is a bold red message'));
console.log(bold().italic('this is a bold italicized message'));
console.log(bold().yellow().bgRed().italic('this is a bold yellow italicized message'));
console.log(green().bold().underline('this is a bold green underlined message'));

Nested Methods

const { yellow, red, cyan } = require('kleur');

console.log(yellow(`foo ${red().bold('red')} bar ${cyan('cyan')} baz`));
console.log(yellow('foo ' + red().bold('red') + ' bar ' + cyan('cyan') + ' baz'));

Conditional Support

Toggle color support as needed; kleur includes simple auto-detection which may not cover all cases.

const kleur = require('kleur');

// manually disable
kleur.enabled = false;

// or use another library to detect support
kleur.enabled = require('color-support').level;

console.log(kleur.red('I will only be colored red if the terminal supports colors'));

API

Any kleur method returns a String when invoked with input; otherwise chaining is expected.

It's up to the developer to pass the output to destinations like console.log, process.stdout.write, etc.

The methods below are grouped by type for legibility purposes only. They each can be chained or nested with one another.

Colors:

black — red — green — yellow — blue — magenta — cyan — white — gray — grey

Backgrounds:

bgBlack — bgRed — bgGreen — bgYellow — bgBlue — bgMagenta — bgCyan — bgWhite

Modifiers:

reset — bold — dim — italic* — underline — inverse — hidden — strikethrough*

* Not widely supported

Benchmarks

Using Node v10.13.0

Load time

chalk       :: 14.543ms
kleur       ::  0.474ms
ansi-colors ::  1.923ms

Performance

# All Colors
  ansi-colors  x 199,381 ops/sec ±1.04% (96 runs sampled)
  chalk        x  12,107 ops/sec ±2.07% (87 runs sampled)
  kleur        x 715,334 ops/sec ±0.30% (93 runs sampled)

# Stacked colors
  ansi-colors  x 24,494 ops/sec ±1.03% (93 runs sampled)
  chalk        x  2,650 ops/sec ±2.06% (85 runs sampled)
  kleur        x 75,798 ops/sec ±0.19% (97 runs sampled)

# Nested colors
  ansi-colors  x  77,766 ops/sec ±0.32% (94 runs sampled)
  chalk        x   5,596 ops/sec ±1.85% (86 runs sampled)
  kleur        x 137,660 ops/sec ±0.31% (93 runs sampled)

Credits

This project originally forked Brian Woodward's awesome ansi-colors library.

Beginning with kleur@3.0, the Chalk-style syntax (magical getter) has been replaced with function calls per key:

// Old:
c.red.bold.underline('old');

// New:
c.red().bold().underline('new');

As I work more with Rust, the newer syntax feels so much better & more natural!

If you prefer the old syntax, you may migrate to ansi-colors. Versions below kleur@3.0 have been deprecated.

License

MIT © Luke Edwards