[js] 实现颜色转换 rgba hex

const hex2Rgba = (bgColor, alpha = 1) => {
  let color = bgColor.slice(1); // 去掉'#'号
  let rgba = [
    parseInt("0x" + color.slice(0, 2)),
    parseInt("0x" + color.slice(2, 4)),
    parseInt("0x" + color.slice(4, 6)),
    alpha
  ];
  return "rgba(" + rgba.toString() + ")";
};

// hex 转 rgba
function hexToRgb(hexValue, opc) {
  var rgx = /^#?([a-f\d])([a-f\d])([a-f\d])$/i;
  var hex = hexValue.replace(rgx, function(m, r, g, b) {
    return r + r + g + g + b + b;
  });
  var rgb = /^#?([a-f\d]{2})([a-f\d]{2})([a-f\d]{2})$/i.exec(hex);
  if(!rgb){
	  return hexValue;
  }
  var r = parseInt(rgb[1], 16);
  var g = parseInt(rgb[2], 16);
  var b = parseInt(rgb[3], 16);
  return 'rgba(' + r + ',' + g + ',' + b + ',' + opc + ')';
}