add method
Adds value
to the end of this list,
extending the length by one.
Throws an UnsupportedError if the list is fixed-length.
If value
already exists in the list, a DuplicateValueError will
be thrown if the list is strict, otherwise the value will just not be
added to the list.
Implementation
@override
void add(E value) {
if (!growable) {
throw UnsupportedError('Cannot add values to a fixed-length list.');
}
if (_contains(value)) {
if (strict) {
throw DuplicateValueError(value);
} else {
return;
}
}
elements.add(value);
}