I am using the geolib npm library, getPreciseDistance function. But I am getting this error:

Cannot read property 'x' of undefined

Here is the code

   var distanceBetweenCenter_DefinedPos = geolib.getPreciseDistance(
        { latitude: startStop.Coordinates['x'], longitude: startStop.Coordinates['y'] },
        { latitude: CenterBetweenStations.Coordinates['x'], longitude: CenterBetweenStations.Coordinates['y'] }       
 );

 console.log(distanceBetweenCenter_DefinedPos);

"CenterBetweenStations" is a variable (code bellow):

 var CenterBetweenStations = geolib.getCenter([
    { latitude: startStop.Coordinates['x'], longitude: startStop.Coordinates['y'] },
    { latitude: nextStop.Coordinates['x'], longitude: nextStop.Coordinates['y'] }
 ]);
 } 

Any ideia how to solve this? Any help would be apreciated.