Typescript support in onChange method for datepicker

[PCPbiscuit]

I'm using DatePicker in my typescript react project and facing an issue regarding onChange method. It returns DateObject so in order to do something with it we have to format/parse it. So I'm using .unix method but Typescript says Property 'unix' does not exist on type 'DateObject | DateObject[]'. Property 'unix' does not exist on type 'DateObject[]'.ts(2339) my DatePicker component:

Datepicker props

type Props = {
  onChange?(selectedDates: DateObject | DateObject[] | null): void;
  value: DateObject | DateObject[] | Date | string[] | null | string | number;
  format?: string;
};

<DatePicker
     value={value}
     onChange={(dates)=>(onChange(dates.unix))}
     format={format}
   />

May be my approach is wrong so don't hesitate to point it out