Color contrast

index.js

/**
* @author David Halford
* @see https://codepen.io/davidhalford/pen/ywEva?editors=0010
* Finds an appropriate contrasting color depending on an rgb color, contains hex to rgb conversion :)
*/

/* about half of 256. Lower threshold equals more dark text on dark background  */
const threshold = 130;

const cutHex = (h) => (h.charAt(0) === '#') ? h.substring(1, 7) : h;

const red = parseInt((cutHex(hexColor)).substring(0, 2), 16);
const green = parseInt((cutHex(hexColor)).substring(2, 4), 16);
const blue = parseInt((cutHex(hexColor)).substring(4, 6), 16);

const cBrightness = ( (red * 299) + ( green * 587 ) + ( blue * 114) ) / 1000;
if (cBrightness > threshold) {
  return //dark color;
} else {
  return // light color;
};