is-dark-color/dist/isDarkColor.js

Detects if a hex color is dark or light. It is based on the w3 documentation for color luminance: https://www.w3.org/TR/WCAG20/#relativeluminancedef

'use strict';

Object.defineProperty(exports, "__esModule", {
  value: true
});
exports.isDarkColor = undefined;

var _hexToRgb2 = require('./hexToRgb');

// adapted from https://stackoverflow.com/a/3943023/491075
var isDarkColor = exports.isDarkColor = function isDarkColor(hexColor, options) {
  if (options && options.override) {
    var overridedColor = Object.keys(options.override).find(function (k) {
      return k.toLowerCase() === hexColor.toLowerCase();
    });
    if (overridedColor !== undefined) {
      return options.override[overridedColor];
    }
  }

  var _hexToRgb = (0, _hexToRgb2.hexToRgb)(hexColor),
      r = _hexToRgb.r,
      g = _hexToRgb.g,
      b = _hexToRgb.b;

  var colorArray = [r / 255, g / 255, b / 255].map(function (v) {
    if (v <= 0.03928) {
      return v / 12.92;
    }

    return Math.pow((v + 0.055) / 1.055, 2.4);
  });

  var luminance = 0.2126 * colorArray[0] + 0.7152 * colorArray[1] + 0.0722 * colorArray[2];

  return luminance <= 0.179;
};