@asamuzakjp/css-color NPM

CSS color

Resolve and convert CSS colors.

Install

npm i @asamuzakjp/css-color

Usage

import { convert, resolve, utils } from '@asamuzakjp/css-color';

const resolvedValue = resolve(
  'color-mix(in oklab, lch(67.5345 42.5 258.2), color(srgb 0 0.5 0))'
);
// 'oklab(0.620754 -0.0931934 -0.00374881)'

const convertedValue = covert.colorToHex('lab(46.2775% -47.5621 48.5837)');
// '#008000'

const result = utils.isColor('green');
// true

resolve(color, opt)

resolves CSS color

Parameters

color string color value
- system colors are not supported
opt object? options (optional, default {})
- opt.currentColor string?
  - color to use for currentcolor keyword
  - if omitted, it will be treated as a missing color, i.e. rgb(none none none / none)
- opt.customProperty object?
  - custom properties
  - pair of -- prefixed property name as a key and it's value, e.g.
```
const opt = {
  customProperty: {
    '--some-color': '#008000',
    '--some-length': '16px'
  }
};
```
  - and/or callback function to get the value of the custom property, e.g.
```
const node = document.getElementById('foo');
const opt = {
  customProperty: {
    callback: node.style.getPropertyValue
  }
};
```
- opt.dimension object?
  - dimension, e.g. for converting relative length to pixels
  - pair of unit as a key and number in pixels as it's value, e.g. suppose 1em === 12px, 1rem === 16px and 100vw === 1024px, then
```
const opt = {
  dimension: {
    em: 12,
    rem: 16,
    vw: 10.24
  }
};
```
  - and/or callback function to get the value as a number in pixels, e.g.
```
const opt = {
  dimension: {
    callback: unit => {
      switch (unit) {
        case 'em':
          return 12;
        case 'rem':
          return 16;
        case 'vw':
          return 10.24;
        default:
          return;
      }
    }
  }
};
```
- opt.format string?
  - output format, one of below
    - computedValue (default), computed value of the color
    - specifiedValue, specified value of the color
    - hex, hex color notation, i.e. #rrggbb
    - hexAlpha, hex color notation with alpha channel, i.e. #rrggbbaa

Returns string? one of rgba?(), #rrggbb(aa)?, color-name, color(color-space r g b / alpha), color(color-space x y z / alpha), (ok)?lab(l a b / alpha), (ok)?lch(l c h / alpha), '(empty-string)', null

in computedValue, values are numbers, however rgb() values are integers
in specifiedValue, returns empty string for unknown and/or invalid color
in hex, returns null for transparent, and also returns null if any of r, g, b, alpha is not a number
in hexAlpha, returns #00000000 for transparent, however returns null if any of r, g, b, alpha is not a number

convert

Contains various color conversion functions.

convert.numberToHex(value)

convert number to hex string

Parameters

value number color value

Returns string hex string: 00..ff

convert.colorToHex(value, opt)

convert color to hex

Parameters

value string color value
opt object? options (optional, default {})
- opt.alpha boolean? return in #rrggbbaa notation
- opt.customProperty object?
  - custom properties, see resolve() function above
- opt.dimension object?
  - dimension, see resolve() function above

Returns string #rrggbb(aa)?

convert.colorToHsl(value, opt)

convert color to hsl

Parameters

value string color value
opt object? options (optional, default {})
- opt.customProperty object?
  - custom properties, see resolve() function above
- opt.dimension object?
  - dimension, see resolve() function above

Returns Array<number> [h, s, l, alpha]

convert.colorToHwb(value, opt)

convert color to hwb

Parameters

value string color value
opt object? options (optional, default {})
- opt.customProperty object?
  - custom properties, see resolve() function above
- opt.dimension object?
  - dimension, see resolve() function above

Returns Array<number> [h, w, b, alpha]

convert.colorToLab(value, opt)

convert color to lab

Parameters

value string color value
opt object? options (optional, default {})
- opt.customProperty object?
  - custom properties, see resolve() function above
- opt.dimension object?
  - dimension, see resolve() function above

Returns Array<number> [l, a, b, alpha]

convert.colorToLch(value, opt)

convert color to lch

Parameters

value string color value
opt object? options (optional, default {})
- opt.customProperty object?
  - custom properties, see resolve() function above
- opt.dimension object?
  - dimension, see resolve() function above

Returns Array<number> [l, c, h, alpha]

convert.colorToOklab(value, opt)

convert color to oklab

Parameters

value string color value
opt object? options (optional, default {})
- opt.customProperty object?
  - custom properties, see resolve() function above
- opt.dimension object?
  - dimension, see resolve() function above

Returns Array<number> [l, a, b, alpha]

convert.colorToOklch(value, opt)

convert color to oklch

Parameters

value string color value
opt object? options (optional, default {})
- opt.customProperty object?
  - custom properties, see resolve() function above
- opt.dimension object?
  - dimension, see resolve() function above

Returns Array<number> [l, c, h, alpha]

convert.colorToRgb(value, opt)

convert color to rgb

Parameters

value string color value
opt object? options (optional, default {})
- opt.customProperty object?
  - custom properties, see resolve() function above
- opt.dimension object?
  - dimension, see resolve() function above

Returns Array<number> [r, g, b, alpha]

convert.colorToXyz(value, opt)

convert color to xyz

Parameters

value string color value
opt object? options (optional, default {})
- opt.customProperty object?
  - custom properties, see resolve() function above
- opt.dimension object?
  - dimension, see resolve() function above
- opt.d50 boolean? xyz in d50 white point

Returns Array<number> [x, y, z, alpha]

convert.colorToXyzD50(value, opt)

convert color to xyz-d50

Parameters

value string color value
opt object? options (optional, default {})
- opt.customProperty object?
  - custom properties, see resolve() function above
- opt.dimension object?
  - dimension, see resolve() function above