How can i calculate the number of days between 2 dates in JavaScript?

I usually prefer moment.js as it is easy to use. check below.

    let startDate = moment('01/01/2020','MM/DD/YYYY');
    let endDate = moment('01/10/2020','MM/DD/YYYY');
    let diffDays = endDate.diff(startDate, 'days');
    console.log(diffDays);