js工具函数-格式化文件大小

function formatFileSize(fileSize, idx = 0) { 
 const units = ["B", "KB", "MB", "GB"]; 
 if (fileSize < 1024 || idx === units.length - 1) { 
 return fileSize.toFixed(1) + units[idx]; 
 } 
 return formatFileSize(fileSize / 1024, ++idx); 
}

function formatFileSize(fileSize, idx) { 
 var units = ["B", "KB", "MB", "GB"]; 
 idx = idx || 0; 
 if (fileSize < 1024 || idx === units.length - 1) { 
 return fileSize.toFixed(1) + units[idx]; 
 } 
 return formatFileSize(fileSize / 1024, ++idx); 
}