How to get days between two different dates in react js inside map function?

Question

How to find the difference between the return date and departure date in ReactJs jsx map loop.

JSON response:

{
    departureDate: '2020-07-28', 
    returnDate: '2020-09-16', 
}

Component

 const DaysDiff = () => {
            const days = 1000 * 60 * 60 * 24;
       return(
         Object.keys(datajson).map((key,index): ReactElement => (

                <h2>{((datajson[key].returnDate) - (datajson[key].departureDate)) / days) } </h2>
    )

     )

    }

Answer 1

Yahoo I resolved my issue. I updated the answer below.

<h2> Math.floor((Date.parse(datajson[key].returnDate) - Date.parse(datajson[key].departureDate)) / days)</h2>

Answer 2

const DaysDiff = () => {
const days = 1000 * 60 * 60 * 24;
return(
    Object.keys(datajson).map((key,index): ReactElement => (
        <h2>{Math.floor(((datajson[key].returnDate) - (datajson[key].departureDate)) / days) )} </h2>
    )
)
}