JAVASCRIPT

firebase timestamp

import firebase from 'firebase';

{
	timestamp: firebase.firestore.FieldValue.serverTimestamp(),
}

firebase query timestamp

Query query = mFirestore.collection("rootcollection")
    .orderBy("timestamp", Query.Direction.DESCENDING)
    .whereEqualTo("month", 3);

timestamp firebase

// Example 4: Compute Timestamp from Java `System.currentTimeMillis()`.

long millis = System.currentTimeMillis();

Timestamp timestamp = 
  Timestamp.newBuilder()
           .setSeconds(millis / 1000)
           .setNanos((int)(millis % 1000 * 1_000_000))
           .build();