define getters throw two events

[justinbmeyer]

Something like:

var AppState = can.Map.extend({
  define: {
    person: {
      get: function(lastSetValue, setAttrValue ) {
        if(lastSetValue) {
          return lastSetValue;
        } else if(this.attr("personId")){
          Person.findOne({id: this.attr("personId")})
            .then(setAttrValue)
        } else {
          return null;
        }
      }
    }
  }
});

If personId is set, person will fire two events.