issue on filter object value

Hi,
I am loading data from array object. but i can't able to filter that column when i load data from object.
i load the data to column like that

` address: {
title: 'City',
valuePrepareFunction: (value) => { return value.cityName },
},`

also i cant able to load two values from the same objects, here address is the object i got cityName from the object, but if i wanna load postalcode from address it shows error

` address: {
title: 'City',
valuePrepareFunction: (value) => { return address.postalCode },
},`

_zone.js:518 ViewWrappedError {__zone_symbol__error: Error: Error in ./ViewCellComponent class ViewCellComponent - inline template:4:30 caused by: Cannot…, _nativeError: ZoneAwareError, originalError: TypeError: Cannot read property 'postalCode' of undefined
at valuePrepareFunction (http://localh…, context: DebugContext}_

also if i use same object name as column name also it shows duplicate error, anyone please help me to find out the solution