Metadata bag for command objects. It's a JSO so that a lightweight JsArray can be used instead of a Collections type.

class Task {

 Object _command;
 bool _repeating = false;

 factory Task.fromRepeatingCommand(RepeatingCommand cmd) {
   return new Task._internal(cmd, true);
 }

 factory Task.fromScheduledCommand(ScheduledCommand cmd) {
   return new Task._internal(cmd, false);
 }

 Task._internal(this._command, this._repeating);

 bool executeRepeating() {
   return getRepeating().execute();
 }

 void executeScheduled() {
   getScheduled().execute();
 }

 /**
  * Has implicit cast.
  */
 RepeatingCommand getRepeating() {
   return _command as RepeatingCommand;
 }

 /**
  * Has implicit cast.
  */
 ScheduledCommand getScheduled() {
   return _command as ScheduledCommand;
 }

 bool isRepeating() {
   return _repeating;
 }
}