Javascript: Add 30 days to date?

Question

I have a dateObject pulled from my database: 2021-01-02T15:12:05.000Z . I'd like to add 30 days to that date so that the end date is: 2021-02-01T15:12:05.000Z . How would I get this to work?

Reading various posts, I've tried:

let storePlanStartDate = dateObject;

storePlanStartDate.setDate(storePlanStartDate.getDate() + 30)

//returns: 1614784325000

I think the return value: 1614784325000 may be what I'm looking for. However, I'm struggling to convert it back to the same format as the original database return so that I can save the updated date.

Answer 1

What you're seeing is just the default representation of a date - dates are stored as number of milliseconds since datum.

If you format the value as an ISO string (for example) you'll see it actually has the value you expected

 let storePlanStartDate = new Date("2021-01-02T15:12:05.000Z"); storePlanStartDate.setDate(storePlanStartDate.getDate() + 30) console.log(storePlanStartDate.toISOString());