Project: /docs/reference/js/_project.yaml Book: /docs/reference/_book.yaml page_type: reference

{% comment %} DO NOT EDIT THIS FILE! This is generated by the JS SDK team, and any local changes will be overwritten. Changes should be made in the source code at https://github.com/firebase/firebase-js-sdk {% endcomment %}

QuerySnapshot class

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

Signature:

typescript

export declare class QuerySnapshot<AppModelType = DocumentData, DbModelType extends DocumentData = DocumentData>

Properties

Property	Type	Description
docs	Array<QueryDocumentSnapshot<!-- --><AppModelType, DbModelType>>	An array of all the documents in the <code>QuerySnapshot</code>.
empty	boolean	True if there are no documents in the <code>QuerySnapshot</code>.
metadata	SnapshotMetadata	Metadata about this snapshot, concerning its source and if it has local modifications.
query	Query<!-- --><AppModelType, DbModelType>	The query on which you called <code>get</code> or <code>onSnapshot</code> in order to get this <code>QuerySnapshot</code>.
size	number	The number of documents in the <code>QuerySnapshot</code>.

Methods

Method	Modifiers	Description
docChanges(options)		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.
forEach(callback, thisArg)		Enumerates all of the documents in the <code>QuerySnapshot</code>.
toJSON()		Returns a JSON-serializable representation of this <code>QuerySnapshot</code> instance.

QuerySnapshot.docs

An array of all the documents in the QuerySnapshot.

Signature:

typescript

get docs(): Array<QueryDocumentSnapshot<AppModelType, DbModelType>>;

QuerySnapshot.empty

True if there are no documents in the QuerySnapshot.

Signature:

typescript

get empty(): boolean;

QuerySnapshot.metadata

Metadata about this snapshot, concerning its source and if it has local modifications.

Signature:

typescript

readonly metadata: SnapshotMetadata;

QuerySnapshot.query

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

Signature:

typescript

readonly query: Query<AppModelType, DbModelType>;

QuerySnapshot.size

The number of documents in the QuerySnapshot.

Signature:

typescript

get size(): number;

QuerySnapshot.docChanges()

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.

Signature:

typescript

docChanges(options?: SnapshotListenOptions): Array<DocumentChange<AppModelType, DbModelType>>;

Parameters

Parameter	Type	Description
options	SnapshotListenOptions	<code>SnapshotListenOptions</code> that control whether metadata-only changes (i.e. only <code>DocumentSnapshot.metadata</code> changed) should trigger snapshot events.

Returns:

Array<DocumentChange<AppModelType, DbModelType>>

QuerySnapshot.forEach()

Enumerates all of the documents in the QuerySnapshot.

Signature:

typescript

forEach(callback: (result: QueryDocumentSnapshot<AppModelType, DbModelType>) => void, thisArg?: unknown): void;

Parameters

Parameter	Type	Description
callback	(result: QueryDocumentSnapshot<!-- --><AppModelType, DbModelType>) => void	A callback to be called with a <code>QueryDocumentSnapshot</code> for each document in the snapshot.
thisArg	unknown	The <code>this</code> binding for the callback.

Returns:

void

QuerySnapshot.toJSON()

Returns a JSON-serializable representation of this QuerySnapshot instance.

Signature:

typescript

toJSON(): object;

Returns:

object

a JSON representation of this object. Throws a FirestoreError if this QuerySnapshot has pending writes.