chromatism/src/operations/contrastRatio.js

A simple set of utility functions for colours.

import convert from '../helpers/convert-to-type'
import makeColourObject from './convert'

export default function contrastRatio (colourRef) {
  var colour = convert('rgb', colourRef)

  var yiq = ((colour.r * 299) + (colour.g * 587) + (colour.b * 114)) / 1000
  if (yiq >= 128) {
    colour = { r: 0, g: 0, b: 0 }
  } else {
    colour = { r: 255, g: 255, b: 255 }
  }

  return makeColourObject(colour)
}