convert method
Converts input
and returns the result of the conversion.
Implementation
@override
String? convert(String? input) {
if (input == null) {
_lastWasBlank = false;
return null;
}
if (input.isEmpty) {
if (_lastWasBlank) {
return null;
} else {
_lastWasBlank = true;
}
} else {
_lastWasBlank = false;
}
return input;
}