JS实现根据文件字节数返回文件大小的方法

function getFileSize(fileByte) {
  var fileSizeByte = fileByte;
  var fileSizeMsg = "";
  if (fileSizeByte < 1048576) fileSizeMsg = (fileSizeByte / 1024) + "KB";
  else if (fileSizeByte == 1048576) fileSizeMsg = "1MB";
  else if (fileSizeByte > 1048576 && fileSizeByte < 1073741824) fileSizeMsg = (fileSizeByte / (1024  1024)) + "MB";
  else if (fileSizeByte > 1048576 && fileSizeByte == 1073741824) fileSizeMsg = "1GB";
  else if (fileSizeByte > 1073741824 && fileSizeByte < 1099511627776) fileSizeMsg = (fileSizeByte / (1024  1024  1024)) + "GB";
  else fileSizeMsg = "文件超过1TB";
  return fileSizeMsg;
}