Flutter: Firebase FieldValue.serverTimestamp() to DateTime object

The FieldValue.serverTimestamp() is not a timestamp, but a so-called sentinel - a marker that gets sent to the server, that the server then recognizes and interprets to write the current timestamp. That means there is no way to convert FieldValue.serverTimestamp() to a timestamp on the client.

What you can do is write FieldValue.serverTimestamp() to a document on the server, and observe the value that is written to that document. This value will be a valid timestamp.

If you have as serverTimeStamp field in your document you can convert it to DateTime as follows;

final DateTime dateTimeFromServerTimeStamp =
 (documentSnapshot.data()['serverTimeStamp'] as Timestamp).toDate();

Assuming you used serverTimeStamp in firebase, and you're reading it back you can read the timestamp read from firebase using DateTime.parse() :

DateTime timestamp = DateTime.parse( json['ts'].toString() );