获取当前base64的大小

const getImgSize = str => {
  var strLength = str.url.length;
  var fileLength = parseInt(strLength - (strLength / 8) * 2);
  var size = '';
  size = (fileLength / 1024).toFixed(2);

  return parseInt(size);
};

       let imgUrl = getImgSize(files[filesIndex]);
       if (imgUrl > 5120) {
         return;
       }