refactor(datasets): extract hooks and components with comprehensive tests (#31707)

Co-authored-by: CodingOnStar <hanxujiang@dify.com>
Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>

web/utils/format.ts

@@ -148,3 +148,23 @@ export const formatNumberAbbreviated = (num: number) => {
 export const formatToLocalTime = (time: Dayjs, local: Locale, format: string) => {
   return time.locale(localeMap[local] ?? 'en').format(format)
 }
+
+/**
+ * Get file extension from file name.
+ * @param fileName file name
+ * @example getFileExtension('document.pdf') will return 'pdf'
+ * @example getFileExtension('archive.tar.gz') will return 'gz'
+ * @example getFileExtension('.gitignore') will return '' (hidden file with no extension)
+ * @example getFileExtension('.hidden.txt') will return 'txt'
+ */
+export const getFileExtension = (fileName: string): string => {
+  if (!fileName)
+    return ''
+
+  // Handle hidden files (starting with dot) by finding dot after the first character
+  const dotIndex = fileName.indexOf('.', fileName.startsWith('.') ? 1 : 0)
+  if (dotIndex === -1 || dotIndex === fileName.length - 1)
+    return ''
+
+  return fileName.slice(dotIndex + 1).split('.').pop()?.toLowerCase() ?? ''
+}