How to calculate difference between two dates in {dd-mm-yyyy} format in react native

Question

I want to calculate the difference between two dates in react native my date format is in {dd-mm-yyyy} I have converted the timestamp using moment and put in a variable that is in format {dd-mm-yyyy hh:mm: ss} so I did is split the date and time so now I have a date in another variable in this format{dd-mm-yyyy} I have tried several methods it is showing me, NaN. here is the code:

const responseJson = [[{"start_date": 1618905463, "end_date" : 1618955463 }]]

var st_date = responseJson[0][0]['start_date']; {
  var time_st = moment.unix(st_date).format("DD-MM-YYYY h:mm:ss");
  setStartDate(time_st)
}
//alert(startdate);
var start = time_st.split(' ')[0];
//alert(start);

var end_date = responseJson[0][0]['end_date']; {
  var time_en = moment.unix(end_date).format("DD-MM-YYYY h:mm:ss");
  setEndDate(time_en)
}
//alert(enddate);
var end = time_en.split(' ')[0];
//alert(end);
date1=startdate;
date2=enddate;
var z = moment('date1', 'DD-MM-YYYY'); 
var w = moment('date2', 'DD-MM-YYYY');
var v = w.diff(z, 'days');
//alert(v);
//alert(diff);
 

<script src="https://cdnjs.cloudflare.com/ajax/libs/moment.js/2.29.1/moment.min.js"></script>

Answer 1

There is no need to go back and forth between moment instances and strings. Once you have used moment.unix to turn a unix time intoa moment instance you can just use it directly to get the number of days (or hours, minutes, seconds as needed) between the two.

const responseJson = [[{"start_date": 1618905463, "end_date" : 1618955463 }]]

var st_date = responseJson[0][0]['start_date']; 
var time_st = moment.unix(st_date)

var end_date = responseJson[0][0]['end_date']; 
var time_en = moment.unix(end_date)

console.log(time_st,time_en);
var v = time_st.diff(time_en, 'days');
console.log(v)

<script src="https://cdnjs.cloudflare.com/ajax/libs/moment.js/2.29.1/moment.min.js"></script>