The eventArgs.getCells() returns array of RowEditCell objects. Each item in array has methods to get references to GridCell and editor and to get/set initial value. Initial value also can be set using getEditor().set_value(newValue).
Target Platforms: Windows 10, Windows 8.1, Windows 8, Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2