parse method

@override Node parse(BlockParser parser)

Implementation

@override
Node parse(BlockParser parser) {
  final match = pattern.firstMatch(parser.current.content)!;
  final matchedText = match[0]!;
  final openMarker = match[1]!;
  final closeMarker = match[2];
  final level = openMarker.length;
  final openMarkerStart = matchedText.indexOf(openMarker);
  final openMarkerEnd = openMarkerStart + level;

  String? content;
  if (closeMarker == null) {
    content = parser.current.content.substring(openMarkerEnd);
  } else {
    final closeMarkerStart = matchedText.lastIndexOf(closeMarker);
    content = parser.current.content.substring(
      openMarkerEnd,
      closeMarkerStart,
    );
  }
  content = content.trim();

  // https://spec.commonmark.org/0.30/#example-79
  if (closeMarker == null && RegExp(r'^#+$').hasMatch(content)) {
    content = null;
  }

  parser.advance();
  return Element('h$level', [if (content != null) UnparsedContent(content)]);
}