事件监听名称
enum Events {
DATABASE_UPGRADE_WILL_START = "DATABASE_UPGRADE_WILL_START", DATABASE_UPGRADING = "DATABASE_UPGRADING", DATABASE_UPGRADE_DID_COMPLETE = "DATABASE_UPGRADE_DID_COMPLETE",}
事件监听器
type EventListeners = { DATABASE_UPGRADE_WILL_START: () => void, DATABASE_UPGRADING: (progress: number) => void, DATABASE_UPGRADE_DID_COMPLETE: (code: ErrorCode) => void,}