Light or dark hex color #color #hex

color.js

export const lightOrDark = (color, ratio = 155) => {
  const hex = color.replace('#', '');
  const red = parseInt(hex.substr(0, 2), 16);
  const green = parseInt(hex.substr(2, 2), 16);
  const blue = parseInt(hex.substr(4, 2), 16);
  const brightness = (red * 299 + green * 587 + blue * 114) / 1000;

  return brightness > ratio ? 'light' : 'dark';
};