"格式化文件大小"

方式1：

function formatFileSize(fileSize) {
  if (fileSize < 1024) {
    return fileSize + 'B';
  } else if (fileSize < (1024*1024)) {
    var temp = fileSize / 1024;
    temp = Math.round(temp);
    return temp + 'KB';
  } else if (fileSize < (1024*1024*1024)) {
    var temp = fileSize / (1024*1024);
    temp = Math.round(temp);
    return temp + 'MB';
  } else {
    var temp = fileSize / (1024*1024*1024);
    temp = Math.round(temp);
    return temp + 'GB';
  }
}

方式2：

const formatSize = (bytes: number): string => {
  if (bytes === 0) return '0 B'
  const k = 1024
  const sizes = ['B', 'KB', 'MB', 'GB', 'TB', 'PB', 'EB', 'ZB', 'YB']
  const i = Math.floor(Math.log(bytes) / Math.log(k))
  const size = parseFloat((bytes / Math.pow(k, i)).toFixed(2))
  return `${size} ${sizes[i]}`
}