get difference value in days in moment js code example

Example 1: momentjs number of days between two dates

var given = moment("2018-03-10", "YYYY-MM-DD");
var current = moment().startOf('day');

//Difference in number of days
moment.duration(given.diff(current)).asDays();

Example 2: moment js difference between two dates

var admission = moment('{date1}', 'DD-MM-YYYY'); 
var discharge = moment('{date2}', 'DD-MM-YYYY');
discharge.diff(admission, 'days');