englishMonth method
Two-digit month numbers → English month names. "01" → "January"
Implementation
String englishMonth() {
const List<String> names = <String>["January", "February", "March", "April", "May", "June", "July", "August", "September", "October", "November", "December"];
final int? n = int.tryParse(trim());
if (n != null && n >= 1 && n <= 12) return names[n - 1];
return this;
}