how to write a javascript for subtracting days from an extracted date?

[shubhamsingh714]

I will get the date from the response of a service in the format YYYY-MM-DD .After extracting the date i need to subtract 28days from the extracted date.How to do it via javascript?

The code which i wrote is below

1st scenario:-

var ss=""
var date="12/22/2017"
var now=new Date(date);

ss=now.setDate(now.getDate()-30)


Output=1511308800000

2nd scenario:-

if i put the code as
var date="12/22/2017"
var now=new Date(date);
now.setDate(now.getDate()-30)

output=Wed Nov 22 2017 00:00:00 GMT-0000 (UTC)

in the 1st scenario,the output which i am getting is this because of i ma setting that to a variable?

how should i assign in to a different variable?
is there a better way to do this? Any help on this?

[DChiesa · Accepted solution]

The JavaScript Date type has a getDate() method, which returns an integer number, between 1 and 31, representing the day of the month for the given date according to local time.

If you want a date from 28 days prior, you would do this:

var dateString = "12/22/2017";
var date1 = new Date(dateString);
var daysPrior = 28;
date1.setDate(date1.getDate() - daysPrior));
print (date1.toISOString()); 

Subtracting days may give you a "negative date", but the setDate() function allows for that and will adjust the month accordingly.

This is independent of Apigee Edge or Rhino. This works in any JavaScript engine.

[#3]

This works great.

If you make a little change, you'll get an even broader solution

var daysToMove = -28;
date1.setDate(date1.getDate() + daysToMove);

Reference to Date.prototype.setDate() if in doubt

https://developer.mozilla.org/es/docs/Web/JavaScript/Reference/Global_Objects/Date/setDate