export function formatFileSize(sizeInBytes: number): string {
  if (sizeInBytes < 1024) {
    return `${sizeInBytes.toFixed(2)} B`;
  } else if (sizeInBytes < 1024 * 1024) {
    const sizeInKB = sizeInBytes / 1024;
    return `${sizeInKB.toFixed(2)} KB`;
  } else {
    const sizeInMB = sizeInBytes / 1024 / 1024;
    return `${sizeInMB.toFixed(2)} MB`;
  }
}

export function getFileExtension(filename: string): string {
  const lastDotIndex = filename.lastIndexOf('.');
  if (lastDotIndex === -1) return ''; // 找不到拓展名
  return filename.slice(lastDotIndex + 1);
}

export function formatFileExtension(ext: string): string {
  return ext.startsWith('.') ? ext.slice(1).toUpperCase() : ext.toUpperCase();
}