extractSectionByHeading function

String? extractSectionByHeading(String markdown, RegExp headingPattern)

Extracts text under first heading matching headingPattern (e.g. r'^#\s+Install'). Audited: 2026-06-12 11:26 EDT

Implementation

String? extractSectionByHeading(String markdown, RegExp headingPattern) {
  final List<String> lines = markdown.split('\n');
  // Find the matching heading; the section body starts on the line after it.
  int start = -1;
  for (int i = 0; i < lines.length; i++) {
    if (headingPattern.hasMatch(lines[i])) {
      start = i + 1;
      break;
    }
  }
  if (start < 0) return null;
  // Collect lines until the NEXT heading (any line starting with '#'), which
  // bounds the section. An all-whitespace body is treated as no section (null).
  final List<String> out = <String>[];
  for (int i = start; i < lines.length; i++) {
    if (lines[i].trimLeft().startsWith('#')) break;
    out.add(lines[i]);
  }
  return out.join('\n').trim().isEmpty ? null : out.join('\n').trim();
}