In What Date Format Should I Store In The Firestore To Create A Dynamic Report Of Per Month?

I have a project to store the vaccination status of the users such as their 1st dose and 2nd dose. I would like to create a dynamic graph reporting for each of the vaccines. And I

Solution 1:

ISO strings are both human readable and sortable:

const date = new Date();
date.toISOString();
// => "2021-08-14T08:01:29.134Z"

If you don’t need readability, epoch time probably better for DB disk space:

const date = new Date();
date.getTime();
// => 1628928089134
// OR
Date.now();
// => 1628928089134

In both cases you can use the returned values to re-create the date object and get the month and year to use for filtering and analysis.

const recreatedDate = new Date("2021-08-14T08:01:29.134Z");
// alternatively:
// const recreatedDate = new Date(1628928089134);

// January is month number 0
recreatedDate.getMonth() + 1
// => 8

console.log(recreatedDate.getFullYear());
// => 2021