@shopify/polaris/src/utilities/color-validation.ts

Shopify’s admin product component library

import type {RGBColor, RGBAColor} from './color-types';

// implements: https://www.w3.org/WAI/ER/WD-AERT/#color-contrast
export function isLight({red, green, blue}: RGBColor | RGBAColor): boolean {
  const contrast = (red * 299 + green * 587 + blue * 114) / 1000;
  return contrast > 125;
}

export function isDark(color: RGBColor | RGBAColor): boolean {
  return !isLight(color);
}