A Timestamp is considered an object:

time = {
  nanoseconds: 0,
  seconds: 1562524200
}

console.log(new Date(time.seconds*1000))

Firebase.ServerValue.TIMESTAMP is a special constant in Firebase that will be replaced with the actual server timestamp value when used within a variable.

mySessionRef.update({ startedAt: Firebase.ServerValue.TIMESTAMP });
mySessionRef.on('value', function(snapshot){ console.log(snapshot.val()) })
//{startedAt: 1470322003}

If you need to retrieve the server time, you can use the following code:

fb.ref("/.info/serverTimeOffset").on('value', function(offset) {
    var offsetVal = offset.val() || 0;
    var serverTime = Date.now() + offsetVal;
});

When working with Firebase Functions, you can easily convert timestamps using the following methods:

timestampObj.toDate()
timestampObj.toMillis().toString()

For more information, check out the documentation here.

It was only effective for me when I utilized

firebase.database.ServerValue.TIMESTAMP

Incorporating one additional 'database' into the namespace.

If you're on the lookout for the Firebase Firestore alternative, check this out:

firebase.firestore.FieldValue.serverTimestamp()

For example:

firebase.firestore().collection("cities").add({
    createdAt: firebase.firestore.FieldValue.serverTimestamp(),
    name: "Paris",
    country: "France"
})
.then(function(docRef) {
    console.log("Document created with ID: ", docRef.id);
})
.catch(function(error) {
    console.error("Error adding document: ", error);
});

Documentation

If you're working with Firestore, Google's cutting-edge database technology, the following code snippet is here to assist you.

var admin    = require("firebase-admin");

var serviceAccount = require("../admin-sdk.json"); // This file is automatically generated by Google Firebase.

admin.initializeApp({
  credential: admin.credential.cert(serviceAccount)
});
var db = admin.firestore();

console.log(admin.firestore.Timestamp.now().toDate());

When working with Firebase, timestamps are provided in the format

{seconds: '', and nanoseconds: ''}

• Assign the Firebase timestamp to a variable, for example: const date

Then, call date.toDate() => This will return the corresponding date.

Update for recent Firebase versions (after Jan 2016)

To add a timestamp to a database update in the most effective way, include a placeholder value in your request. The following example demonstrates how Firebase will replace the createdAt property with a timestamp:

const firebaseRef = firebase.database().ref();
firebaseRef.set({
  foo: "bar", 
  createdAt: firebase.database.ServerValue.TIMESTAMP
});

As stated in the documentation, the value of

firebase.database.ServerValue.TIMESTAMP

Need a foolproof way to switch from firebase Timestamp type to JS Date? Look no further! This method will do the trick, and if the value isn't a Timestamp, it'll simply return it as is.

Perfect for Angular versions 7 through 9

import firebase from 'firebase';
import Timestamp = firebase.firestore.Timestamp;

export function translateTimestampIntoDate(timestamp: Timestamp | any): Date | any {
  return timestamp instanceof Timestamp
    ? new Timestamp(timestamp.seconds, timestamp.nanoseconds).toDate()
    : timestamp;
}

Give this a shot:

let currentDate = new Date().toISOString()
let formattedDate = currentDate.split('T')[0]

Utilizing Firebase Firestone version 18.0.1 (com.google.firebase.Timestamp)

extracting a timestamp from the document data using Firestore (document.data["timestamp"] as Timestamp).toDate()

To easily obtain the server timestamp in milliseconds, you can use the following function just once:

var getServerTime = function( cb ) {
    this.db.ref( '.info/serverTimeOffset' ).once( 'value', function( snap ) {
      var offset = snap.val();

      // Get server time in milliseconds
      cb( new Date().getTime() + offset );
    });
};

After defining the function, you can call it anywhere like this:

getServerTime( function( now ) {
    console.log( now );
});

Advantages of this approach

According to the latest Firebase documentation, converting Firebase timestamps to milliseconds is recommended. Here's how you can achieve that using the estimatedServerTimeMs variable:

var offsetRef = firebase.database().ref(".info/serverTimeOffset");
offsetRef.on("value", function(snap) {
  var offset = snap.val();
  var estimatedServerTimeMs = new Date().getTime() + offset;
});

While firebase.database.ServerValue.TIMESTAMP is more accurate and generally preferred for read/write operations, estimating clock skew between client and server can be useful in certain cases. By accessing /.info/serverTimeOffset, clients can determine the difference in reported local time and server time in milliseconds. This offset may not always be perfectly accurate due to network latency but can help identify significant discrepancies in clock time.

https://firebase.google.com/docs/database/web/offline-capabilities

Convert timestamp to a UTC string using the new Date method

    import firebaseApp from 'firebase/app';


    function convertDateToFirestoreTime(date: Date) {
       return firebaseApp.firestore.Timestamp.fromDate(date).toMillis()
    }
    function convertFirestoreTimeToDate(millisecDate: number) {
       return firebaseApp.firestore.Timestamp.fromMillis(millisecDate).toDate()
    }


    // Example:
    let firestoreTimestampNow = convertDateToFirestoreTime(new Date())
    console.log('Converting current date to Firestore Timestamp:', firestoreTimestampNow)
    let convertedDateNow = convertFirestoreTimeToDate(firestoreTimestampNow)
    console.log('Converting Firestore Timestamp back to Date Object:', convertedDateNow)

The exact snippet of code that successfully worked for me involved iterating through this.

querySnapshot.documents.forEach((entry) => {
   let dateValue = entry.data().date.toDate();
   console.log(dateValue);
}

In my experience, the timeStamp needs to be in integer format rather than a string for it to function correctly:

var time = '1452488445471';
var currentDate = new Date(parseInt(time));
currentDate.toDateString()

I transformed the data into a different structure

const unixTimestamp = '1452488445471';
const newDate = new Date(unixTimestamp * 1000)
const hours = newDate.getHours()
const minutes = newDate.getMinutes()
const formattedTime = `${hours}:${minutes}`
console.log(formattedTime)

const time = new Date(date.seconds * 1000 + date.nanoseconds / 1000000);

To properly utilize the .toDate() function, you may need to explicitly specify the type like so:

import { Timestamp } from "firebase/firestore";
...
(dateVariable as unknown as Timestamp).toDate()

By following this syntax, the .toDate() method will function correctly.