Abstract Readonly $$isReadonly indexProtected isAbstract itemReadonly itemsset it True, the follow emit will be ignore and then set it False.
Protected _addProtected _clearProtected _removeAbstract createOptional payload: PlainObjectsplit fire
Optional payload: PlainObjectCreate parent-child relationships of two evented objects manually. Because this method not mounted on evented object.
Optional off: booleanGenerated using TypeDoc
key to item.