getParagraphAfter method
Implementation
Paragraph? getParagraphAfter(Paragraph paragraph) {
if (paragraphs.isEmpty) return null;
final int index =
paragraphs.indexWhere((pr) => pr.id == paragraph.id || pr == paragraph);
if (index < 0 && (index + 1) >= paragraphs.length) return null;
return paragraphs.elementAt(index + 1);
}