let appBackHandler ; let networkLoggerBackHandler ; export const setBackHandler = ( backHandler ? ) => { networkLoggerBackHandler = backHandler ; } ; const goBack = ( ) => { if ( networkLoggerBackHandler ) { return networkLoggerBackHandler ( ) ; } appBackHandler ?. ( ) ; } ; export const backHandlerSet = ( ) => { return ! ! appBackHandler ; } ; param backHandler export const getBackHandler = ( backHandler ) => { appBackHandler = backHandler ; return goBack ; } ;