QuerySnapshot

class

Constructor

QuerySnapshot

new QuerySnapshot()

A QuerySnapshot contains zero or more QueryDocumentSnapshot objects representing the results of a query. The documents can be accessed as an array via the documents property or enumerated using the forEach method. The number of documents can be determined via the empty and size properties.

Properties

docs

read-only

Array of QueryDocumentSnapshot

An array of all the documents in this QuerySnapshot.

Example 

let query = firestore.collection('col').where('foo', '==', 'bar');

query.get().then(querySnapshot => {
  let docs = querySnapshot.docs;
  for (let doc of docs) {
    console.log(`Document found at path: ${doc.ref.path}`);
  }
});

empty

read-only

boolean

True if there are no documents in the QuerySnapshot.

Example 

let query = firestore.collection('col').where('foo', '==', 'bar');

query.get().then(querySnapshot => {
  if (querySnapshot.empty) {
    console.log('No documents found.');
  }
});

query

read-only

Query

The query on which you called get() or onSnapshot() in order to get this QuerySnapshot.

Example 

let query = firestore.collection('col').where('foo', '==', 'bar');

query.limit(10).get().then(querySnapshot => {
  console.log(`Returned first batch of results`);
  let query = querySnapshot.query;
  return query.offset(10).get();
}).then(() => {
  console.log(`Returned second batch of results`);
});

readTime

Timestamp

The time this query snapshot was obtained.

Example 

let query = firestore.collection('col').where('foo', '==', 'bar');

query.get().then((querySnapshot) => {
  let readTime = querySnapshot.readTime;
  console.log(`Query results returned at '${readTime.toDate()}'`);
});

size

read-only

number

The number of documents in the QuerySnapshot.

Example 

let query = firestore.collection('col').where('foo', '==', 'bar');

query.get().then(querySnapshot => {
  console.log(`Found ${querySnapshot.size} documents.`);
});

Methods

docChanges

docChanges() returns Array of DocumentChange

Returns an array of the documents changes since the last snapshot. If this is the first snapshot, all documents will be in the list as added changes.

Returns

Array of DocumentChange 

Example 

let query = firestore.collection('col').where('foo', '==', 'bar');

query.onSnapshot(querySnapshot => {
  let changes = querySnapshot.docChanges();
  for (let change of changes) {
    console.log(`A document was ${change.type}.`);
  }
});

forEach

forEach(callback, thisArg)

Enumerates all of the documents in the QuerySnapshot.

Parameter

callback

function()

A callback to be called with a QueryDocumentSnapshot for each document in the snapshot.

thisArg

Optional

any type

The this binding for the callback..

Example 

let query = firestore.collection('col').where('foo', '==', 'bar');

query.get().then(querySnapshot => {
  querySnapshot.forEach(documentSnapshot => {
    console.log(`Document found at path: ${documentSnapshot.ref.path}`);
  });
});

isEqual

isEqual(other) returns boolean

Returns true if the document data in this QuerySnapshot is equal to the provided value.

Parameter

other

any type

The value to compare against.
Returns

boolean 

true if this QuerySnapshot is equal to the provided value.