Develop Reference

How to update Firestore Timestamp to a future value

We have a check-in and check-out component in our web app that simply uses firebase timestamps. However, we need the ability to edit those timestamps in the event someone makes a mistake.
checkInTimeStamp: fb.firestore.FieldValue.serverTimestamp("17:00") simply returns the current time.
Instead of 17:00, what object do we need to pass through the function to get the correct timestamp?

The serverTimestamp() generates current timestamp on server side. You can use a Date object instead to store a future date:
const futureDate = new Date();
// update date to future time
futureDate.setDate(futureDate.getDate() + 5);
db.document('col/doc').set({ checkInTimeStamp: futureDate })
Checkout other method like setDate() in MDN docs.

MongoDB Stored my date with the wrong time

I recently tried to assign a new date in MongoDB, but I have a problem with that, it stored the date I give but it's not correct
userSchema.methods.createPasswordResetToken = async function () {
this.passwordResetToken = crypto.randomBytes(20).toString('hex')
this.passwordResetExpires = moment().format(this.createAt)
await this.save()
console.log(moment().format(this.createAt)) // 2021-12-21T19:01:54+02:00
console.log(this.passwordResetExpires) // 2021-12-21T17:01:54.000Z
return { token: this.passwordResetToken, userId: this._id }
}
mongoDb remove 2 hours when storing it
and when I try to catch the type of two values
I got
console.log(moment().format(this.createAt)) // string
console.log(this.passwordResetExpires) // object
:
user Schema
...
passwordResetToken: String,
passwordResetExpires: Date
...

From the docs:
MongoDB stores times in UTC by default, and will convert any local time representations into this form. Applications that must operate or report on some unmodified local time value may store the time zone alongside the UTC timestamp, and compute the original local time in their application logic.
It seems your server just sits in GMT timezone ( utc +2, you could also see it from your date value // 2021-12-21T19:01:54+02:00 ). I would usually offer some hacky way to get around the issue but this is actually a best practice. Hence I recommend you do your date calculations in UTC and not in machine time.
note your other date is in UTC (2021-12-21T17:01:54.000Z), make sure your comparing apples to apples.

Get JavaScript local date from Moment JS

Consider the code :
let now = moment();
console.log(now.format()); // 2019-11-25T20:23:50+02:00
console.log(now.toDate()); // 2019-11-25T18:23:50.916Z
This is the output on my local machine , and when I check the app on Heroku
it gives the same values , even though I changed the TZ like this :
heroku config:add TZ="Asia/Jerusalem"
How can I get a JavaScript Date (Not a String !) object of my localtime , meaning 2019-11-25T20:23:50 ?

Let's walk through your code example:
let now = moment();
You create a Moment object. You don't pass any parameters, so it is initialized using the current timestamp (as if you called Date.now()) and set to "local mode".
console.log(now.format()); // 2019-11-25T20:23:50+02:00
By calling format, you ask the Moment object to produce a String. Since it's in local mode, the offset that applies to that moment in time for the local time zone is emitted in the result, and the wall time shown in the result is adjusted for that offset. In this case, the local time is two hours ahead of UTC. You then pass that string to console.log, which emits it to the console.
console.log(now.toDate()); // 2019-11-25T18:23:50.916Z
By calling toDate, you ask the Moment object to create a Date object. The "mode" of the moment object is no longer relevant because Date objects don't track anything other than a timestamp. Thus, the timestamp within the Moment object becomes the timestamp for the resulting Date object. Since you derived the Moment object from the current time, the result is the same as if you just called new Date() to begin with.
You then pass the string to console.log - except one can't just log an object, so it first has to convert it to something so you can see it. Here's the interesting part: There is no spec for this behavior. Implementations of ECMAScript can do whatever they like in this regard. Some implementations, like in your example, will call .toISOString() and log the result. Since .toISOString() displays the result in UTC, the result of logging a Date object is also shown in UTC. But other implementations will call .toString() on the Date object and log that, the result being in local time. It's entirely possible some future implementation could show the result in some graphical or interactive output. The point being, you can't rely on the behavior of console.log(Date) to be consistent.
No amount of changing your time zone settings will change this result. The Date object is inherently UTC-based, your output is also UTC-based, and UTC is the same over the whole planet (by design).
If you want the time zone reflected in the string output, you must use a function that produces a string with respect to local time. As you showed, you'll get that with .format() on a Moment object in local mode. You can also get one from calling .toString() on a Date object (but the resulting string is not in the same ISO 8601 format).

i would try,
moment().local().toDate()
but if you are planning to save date into db it's good practice to save time in UTC format for easier global conversion.
If you want to work timezones you may require also moment timezone package - https://momentjs.com/timezone/docs/
npm install moment-timezone
Hope this helps :)

get date from firebase format change

earlier we push date use native Firebase format
createAt:admin.firestore.Timestamp.fromDate(new Date)
so data store like this
"createAt": {
"_seconds": 1563181560,
"_nanoseconds": 567000000
}
new we change like this
createAt:new Date().toISOString()
now store like this
"createAt": "2019-07-17T07:17:05.115Z"
buts some date store like this because we use native date format
now how can i call old date to new date format? moste of the data sote like native date method is that any way to change new method?

The Firestore Timestamp type has many conversion methods. Just like it has a fromDate() it also has a toDate() method. So if you reload the data from Firestore and get a Timestamp object, you can then get a date with timestamp.toDate() and thus an ISO-8859 formatted string with timestamp.toDate().toISOString().

Create timezone-aware date in javascript

When I create objects in my MongoDB using Mongoose, the dates are formatted as, for instance, 2016-10-10T15:35:52.764Z (it might be yyyy-MM-ddTHH:mm:ssZ). If I use Date.now() in JavaScript, I get a timestamp.
How can I create the same date format as Mongoose with javascript?
Edit
It seems I can use
new Date().toISOString();
but what is the difference of, for instance, Date.now() and new Date()?
Are there any reasons for not using new Date() instead of a function under the Date object (that somehow already seems to be initialized without writing new Date()?)

you can use moment.js and run like this
moment().format('YYYY-MM-DDTHH:mm:ss'); // print 2016-10-11T15:25:36