🌈 color2k

a color parsing and manipulation lib served in roughly 2kB or less (2.8kB to be more precise)

color2k is a color parsing and manipulation library with the objective of keeping the bundle size as small as possible while still satisfying all of your color manipulation needs in an sRGB space.

The full bundle size is currently 2.8kB but gets as small as 2.1k with tree shaking.

Table of contents

• Size comparison
• Installation
• Usage
• How so small?
• Trust and publishing
• Credits
• API

Size comparison

lib	size
chroma-js	13.7kB
polished	11.2kB
color	7.6kB
tinycolor2	5kB
color2k	2.8kB 😎

👋 Compare tree-shaken bundle outputs on bundlejs.com

Installation

Install with a package manager such as npm

npm i color2k

OR use with skypack.dev in supported environments (e.g. deno, modern browsers).

import { darken, transparentize } from 'https://cdn.skypack.dev/color2k?min';

Usage

import { darken, transparentize } from 'color2k';

// e.g.
darken('blue', 0.1);
transparentize('red', 0.5);

How so small?

There are two secrets that keep this lib especially small:

1. Simplicity — only handles basic color manipulation functions
2. Less branching in code — only support two color models as outputs, namely rgba and hsla

Why only rgba and hsla as outputs?

This lib was created with the use case of CSS-in-JS in mind. At the end of the day, all that matters is that the browser can understand the color string you gave it as a background-color.

Because only those two color models are supported, we don't have to add code to deal with optional alpha channels or converting to non-browser supported color models (e.g. CMYK).

We believe that this lib is sufficient for all of your color manipulation needs. If we're missing a feature, feel free to open an issue 😎.

Trust and publishing

color2k is intentionally small and boring:

• Zero runtime dependencies.
• A narrow published package surface, limited to dist, README.md, LICENSE, and package.json.
• npm provenance is configured through trusted publishing for release builds.
• The README and docs site are generated from the JSDoc comments in src/*.ts.
• Security issues can be reported through the process in SECURITY.md.

Before publishing, maintainers should run the checks in docs/release-checklist.md.

Credits

Heavy credit goes to polished.js and Sass. Much of the implementation of this lib is copied from polished.

API

This section is generated from the JSDoc comments in src/*.ts.

adjustHue(color, degrees)

function adjustHue(color: string, degrees: number): string

Rotates a color's hue by the given number of degrees and returns the result as an hsla string. Hue values wrap around the 0 to 360 degree color wheel.

adjustHue('red', 180); // 'hsla(180, 100%, 50%, 1)'

Parameters

Name	Type	Description
color	string	The input color.
degrees	number	The number of degrees to rotate the hue.

Returns

string - The adjusted color as an hsla string.

Source

ColorError

class ColorError extends Error

Error thrown when color2k cannot parse an input color.

new ColorError('nope').message; // 'Failed to parse color: "nope"'

Constructor Parameters

Name	Type	Description
color	string	The color value that failed to parse.

Source

darken(color, amount)

function darken(color: string, amount: number): string

Darkens a color by subtracting from the lightness channel in HSL space.

darken('white', 0.1); // 'hsla(0, 0%, 90%, 1)'

Parameters

Name	Type	Description
color	string	The input color.
amount	number	The amount to darken, given as a decimal between 0 and 1.

Returns

string - The darkened color as an hsla string.

Source

desaturate(color, amount)

function desaturate(color: string, amount: number): string

Desaturates a color by subtracting from the saturation channel in HSL space.

desaturate('red', 0.5); // 'hsla(0, 50%, 50%, 1)'

Parameters

Name	Type	Description
color	string	The input color.
amount	number	The amount to desaturate, given as a decimal between 0 and 1.

Returns

string - The desaturated color as an hsla string.

Source

getContrast(color1, color2)

function getContrast(color1: string, color2: string): number

Returns the contrast ratio between two colors based on the WCAG contrast ratio formula.

getContrast('#444', '#fff'); // 9.739769120526205

Parameters

Name	Type	Description
color1	string	The first color.
color2	string	The second color.

Returns

number - The contrast ratio between the two colors.

Source

getLuminance(color)

function getLuminance(color: string): number

Returns the relative luminance of a color using the WCAG formula.

getLuminance('papayawhip'); // 0.877971001998354

Parameters

Name	Type	Description
color	string	The input color.

Returns

number - A number between 0 for darkest black and 1 for lightest white.

Source

getScale(colors)

function getScale(colors: string[]): (n: number) => string

Returns a scale function that interpolates through a list of colors.

The returned function accepts a decimal between 0 and 1 and returns the color at that percentage in the scale.

const scale = getScale('red', 'yellow', 'green');
console.log(scale(0)); // rgba(255, 0, 0, 1)
console.log(scale(0.5)); // rgba(255, 255, 0, 1)
console.log(scale(1)); // rgba(0, 128, 0, 1)

If you'd like to limit the domain and range like chroma-js, we recommend wrapping scale again.

const _scale = getScale('red', 'yellow', 'green');
const scale = x => _scale(x / 100);

console.log(scale(0)); // rgba(255, 0, 0, 1)
console.log(scale(50)); // rgba(255, 255, 0, 1)
console.log(scale(100)); // rgba(0, 128, 0, 1)

Parameters

Name	Type	Description
colors	string[]	The colors to interpolate through.

Returns

(n: number) => string - A function that maps a decimal percentage to an rgba color.

Source

guard(low, high, value)

function guard(low: number, high: number, value: number): number

Clamps a number between a lower and upper bound.

guard(0, 1, 2); // 1

Parameters

Name	Type	Description
low	number	The lower bound.
high	number	The upper bound.
value	number	The number to clamp.

Returns

number - The clamped number.

Source

hasBadContrast(color, standard, background)

function hasBadContrast(color: string, standard: 'decorative' | 'readable' | 'aa' | 'aaa' = 'aa', background: string = '#fff'): boolean

Returns whether a color fails a contrast threshold against a background.

The supported standards are decorative, readable, aa, and aaa.

hasBadContrast('red', 'aa'); // true

Parameters

Name	Type	Description
color	string	The foreground color.
standard	'decorative' | 'readable' | 'aa' | 'aaa' = 'aa'	The contrast standard to test against.
background	string = '#fff'	The background color.

Returns

boolean - true when the contrast ratio is below the selected standard.

Source

hsla(hue, saturation, lightness, alpha)

function hsla(hue: number, saturation: number, lightness: number, alpha: number): string

Builds an hsla color string from hue, saturation, lightness, and alpha channel values.

hsla(0, 1, 0.5, 1); // 'hsla(0, 100%, 50%, 1)'

Parameters

Name	Type	Description
hue	number	The color wheel angle from 0 to 360.
saturation	number	The saturation as a decimal between 0 and 1.
lightness	number	The lightness as a decimal between 0 and 1.
alpha	number	The opacity as a decimal between 0 and 1.

Returns

string - An hsla color string.

Source

lighten(color, amount)

function lighten(color: string, amount: number): string

Lightens a color by adding to the lightness channel in HSL space.

This is equivalent to darken(color, -amount).

lighten('black', 0.1); // 'hsla(0, 0%, 10%, 1)'

Parameters

Name	Type	Description
color	string	The input color.
amount	number	The amount to lighten, given as a decimal between 0 and 1.

Returns

string - The lightened color as an hsla string.

Source

mix(color1, color2, weight)

function mix(color1: string, color2: string, weight: number): string

Mixes two colors together using the Sass mix algorithm and returns an rgba color string.

mix('red', 'blue', 0.5); // 'rgba(128, 0, 128, 1)'

Parameters

Name	Type	Description
color1	string	The first color.
color2	string	The second color.
weight	number	The mix weight as a decimal between 0 and 1.

Returns

string - The mixed color as an rgba string.

Source

opacify(color, amount)

function opacify(color: string, amount: number): string

Makes a color more opaque by increasing the alpha channel.

This is equivalent to transparentize(color, -amount).

opacify('rgba(255, 255, 255, 0.5)', 0.1); // 'rgba(255, 255, 255, 0.6)'

Parameters

Name	Type	Description
color	string	The input color.
amount	number	The amount to increase opacity by, given as a decimal between 0 and 1.

Returns

string - The more opaque color as an rgba string.

Source

parseToHsla(color)

function parseToHsla(color: string): [number, number, number, number]

Parses a color into hue, saturation, lightness, and alpha channel values.

Hue is a number between 0 and 360. Saturation, lightness, and alpha are decimal percentages between 0 and 1.

parseToHsla('red'); // [0, 1, 0.5, 1]

Parameters

Name	Type	Description
color	string	The input color.

Returns

[number, number, number, number] - A tuple of hue, saturation, lightness, and alpha values.

Source

parseToRgba(color)

function parseToRgba(color: string): [number, number, number, number]

Parses a color into red, green, blue, and alpha channel values.

Supports hex, RGB, RGBA, HSL, HSLA, CSS named colors, and transparent.

parseToRgba('rgba(255, 0, 0, 0.5)'); // [255, 0, 0, 0.5]

Parameters

Name	Type	Description
color	string	The input color.

Returns

[number, number, number, number] - A tuple of red, green, blue, and alpha channel values.

Source

readableColor(color)

function readableColor(color: string): string

Returns black or white, whichever has better contrast against the given color.

readableColor('white'); // '#000'

Parameters

Name	Type	Description
color	string	The background color.

Returns

string - #000 or #fff.

Source

readableColorIsBlack(color)

function readableColorIsBlack(color: string): boolean

Returns whether black is the more readable color to place on top of the input color.

This is the boolean form of readableColor.

readableColorIsBlack('white'); // true

Parameters

Name	Type	Description
color	string	The background color.

Returns

boolean - true when black is the more readable foreground color.

Source

rgba(red, green, blue, alpha)

function rgba(red: number, green: number, blue: number, alpha: number): string

Builds an rgba color string from red, green, blue, and alpha channel values.

rgba(255, 0, 0, 1); // 'rgba(255, 0, 0, 1)'

Parameters

Name	Type	Description
red	number	The red channel value from 0 to 255.
green	number	The green channel value from 0 to 255.
blue	number	The blue channel value from 0 to 255.
alpha	number	The opacity as a decimal between 0 and 1.

Returns

string - An rgba color string.

Source

saturate(color, amount)

function saturate(color: string, amount: number): string

Saturates a color by adding to the saturation channel in HSL space.

This is equivalent to desaturate(color, -amount).

saturate('hsl(0, 50%, 50%)', 0.1); // 'hsla(0, 60%, 50%, 1)'

Parameters

Name	Type	Description
color	string	The input color.
amount	number	The amount to saturate, given as a decimal between 0 and 1.

Returns

string - The saturated color as an hsla string.

Source

toHex(color)

function toHex(color: string): string

Converts a color to a hex color string.

Includes an alpha channel when the input color is not fully opaque.

toHex('palevioletred'); // '#db7093'

Parameters

Name	Type	Description
color	string	The input color.

Returns

string - A hex color string.

Source

toHsla(color)

function toHsla(color: string): string

Converts a color to an hsla color string.

toHsla('peachpuff'); // 'hsla(28, 100%, 86%, 1)'

Parameters

Name	Type	Description
color	string	The input color.

Returns

string - An hsla color string.

Source

toRgba(color)

function toRgba(color: string): string

Converts a color to an rgba color string.

toRgba('midnightblue'); // 'rgba(25, 25, 112, 1)'

Parameters

Name	Type	Description
color	string	The input color.

Returns

string - An rgba color string.

Source

transparentize(color, amount)

function transparentize(color: string, amount: number): string

Makes a color more transparent by decreasing the alpha channel.

transparentize('white', 0.1); // 'rgba(255, 255, 255, 0.9)'

Parameters

Name	Type	Description
color	string	The input color.
amount	number	The amount to increase transparency by, given as a decimal between 0 and 1.

Returns

string - The more transparent color as an rgba string.

Source