Javascript parse colours (Hex to RGB and vice versa) as well as luminance(dark or bright)

colours.js

/**
 * Original code from https://github.com/mike-schultz/materialette
 */

function rgbToHex(r, g, b) {
  return "#" + ((1 << 24) + (parseInt(r) << 16) + (parseInt(g) << 8) + parseInt(b)).toString(16).slice(1);
}

function hexToRgb(hex) {
  const result = /^#?([a-f\d]{2})([a-f\d]{2})([a-f\d]{2})$/i.exec(hex);
  return result ? {
    r: parseInt(result[1], 16),
    g: parseInt(result[2], 16),
    b: parseInt(result[3], 16)
  } : null;
}


/**
 * luminance(hex, '#fff', '#000')
 */
function luminance(sHexColor, sLight, sDark) {
  const oRGB = hexToRgb(sHexColor);
  const yiq = ((oRGB.r * 299) + (oRGB.g * 587) + (oRGB.b * 114)) / 1000;
  return (yiq >= 128) ? sDark : sLight;
}