add method

bool add(
  1. E valueToAdd
)

Adds value to the set.

Returns true if value (or an equal value) was not yet in the set. Otherwise returns false and the set is not changed.

Example:

final dateTimes = <DateTime>{};
final time1 = DateTime.fromMillisecondsSinceEpoch(0);
final time2 = DateTime.fromMillisecondsSinceEpoch(0);
// time1 and time2 are equal, but not identical.
assert(time1 == time2);
assert(!identical(time1, time2));
final time1Added = dateTimes.add(time1);
print(time1Added); // true
// A value equal to time2 exists already in the set, and the call to
// add doesn't change the set.
final time2Added = dateTimes.add(time2);
print(time2Added); // false

print(dateTimes); // {1970-01-01 02:00:00.000}
assert(dateTimes.length == 1);
assert(identical(time1, dateTimes.first));
print(dateTimes.length);

Implementation

bool add(E valueToAdd) {
  late bool _result;
  update((_) => _result = value.add(valueToAdd));
  return _result;
}