extractTag function
Extract content from an XML-like tag in a string.
Implementation
String? extractTag(String html, String tagName) {
if (html.trim().isEmpty || tagName.trim().isEmpty) return null;
final escapedTag = RegExp.escape(tagName);
final pattern = RegExp(
'<$escapedTag(?:\\s+[^>]*)?>([\\s\\S]*?)</$escapedTag>',
caseSensitive: false,
);
final match = pattern.firstMatch(html);
if (match != null) {
final content = match.group(1);
if (content != null && content.isNotEmpty) return content;
}
return null;
}