ordinal method
Implementation
@override
String ordinal(int number) {
assert(number != 0);
if (number == -1) return 'last';
final n = number.abs();
String string;
if (n % 10 == 1 && n % 100 != 11) {
string = '${n}st';
} else if (n % 10 == 2 && n % 100 != 12) {
string = '${n}nd';
} else if (n % 10 == 3 && n % 100 != 13) {
string = '${n}rd';
} else {
string = '${n}th';
}
return number < 0 ? '$string-to-last' : string;
}