packJsonContent = () => {
    if (jsonContent.length > 0) {
      left = new Item(createID(ownClientId, getState(store, ownClientId)), left, left && left.lastId, right, right && right.id, parent, null, new ContentAny(jsonContent));
      left.integrate(transaction, 0);
      jsonContent = [];
    }
  }
@type {Array<Object|Array<any>|number|null>}