WCAG Color


According to the WHO an estimated 1.3 billion
people live with some form of visual impairment. This includes people who are legally blind and people with less than 20/20 vision.

This library helps you achieve the accessibility standards for color contrast outlined in the WCAG 2.0 specification.

Installation

``
npm install wcag-color
`

API

$3

ratio takes two colors, a foreground color, and background color, and returns a contrast ratio. ratio accepts most color formats:

- HEX - normal (#0088ff), shorthand (#08f) and without hash (08f)
- RGB - rgb(255, 255, 255)
- HSL - hsl(210, 100%, 40%)

`js
ratio(foreground: string, background: string) => number
`

#### Example

`js
import { ratio } from 'wcag-color'

ratio('hsl(210, 100%, 40%)', '#ffffff') // 5.57
`

$3

score takes two colors and returns a score value. Read more below.

`js
score(foreground: string, background: string) => 'Fail' | 'AA Large' | 'AA' | 'AAA'
`

#### Example

`js
import { score } from 'wcag-color'

score('hsl(210, 100%, 40%)', '#ffffff') // AA
`

$3

scoreFromRatio takes a ratio and returns a score value.

`js
scoreFromRatio(ratio: number) => 'Fail' | 'AA Large' | 'AA' | 'AAA'
`

#### Example

`js
import { scoreFromRatio } from 'wcag-color'

scoreFromRatio(7.5) // AAA
`

$3

best takes two colors and a background color and returns the color which is
best suited, from a contrast perspective, for that background color.

`js
best(firstColor: string, secondColor: string, background: string) => string
`

#### Example

`js
import { best } from 'wcag-color'

best('#ffffff', '#000000', '#ffffff') // #000000
`

Score and ratio

- Fail - Your text has a contrast ratio of less than 3.0
- AA Large - Least amount of contrast for font size 18px and larger. The ratio is above 3.0.
- AA - What you should aim for with text sizes below 18px. The ratio is at least 4.5.
- AAA - Enhanced contrast with a ratio of at least 7.0`. Valuable for texts that will be read for a longer period of time.