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DocumentSnapshot class

A DocumentSnapshot contains data read from a document in your Firestore database. The data can be extracted with .data() or .get(<field>) to get a specific field.

For a DocumentSnapshot that points to a non-existing document, any data access will return 'undefined'. You can use the exists() method to explicitly verify a document's existence.

Signature:

typescript

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

Constructors

Constructor	Modifiers	Description
(constructor)()		Constructs a new instance of the <code>DocumentSnapshot</code> class

Properties

Property	Modifiers	Type	Description
id		string	Property of the <code>DocumentSnapshot</code> that provides the document's ID.
ref		DocumentReference<!-- --><AppModelType, DbModelType>	The <code>DocumentReference</code> for the document included in the <code>DocumentSnapshot</code>.

Methods

Method	Modifiers	Description
data()		Retrieves all fields in the document as an <code>Object</code>. Returns <code>undefined</code> if the document doesn't exist.
exists()		Signals whether or not the document at the snapshot's location exists.
get(fieldPath)		Retrieves the field specified by <code>fieldPath</code>. Returns <code>undefined</code> if the document or field doesn't exist.

DocumentSnapshot.(constructor)

Constructs a new instance of the DocumentSnapshot class

Signature:

typescript

protected constructor();

DocumentSnapshot.id

Property of the DocumentSnapshot that provides the document's ID.

Signature:

typescript

get id(): string;

DocumentSnapshot.ref

The DocumentReference for the document included in the DocumentSnapshot.

Signature:

typescript

get ref(): DocumentReference<AppModelType, DbModelType>;

DocumentSnapshot.data()

Retrieves all fields in the document as an Object. Returns undefined if the document doesn't exist.

Signature:

typescript

data(): AppModelType | undefined;

Returns:

AppModelType | undefined

An Object containing all fields in the document or undefined if the document doesn't exist.

DocumentSnapshot.exists()

Signals whether or not the document at the snapshot's location exists.

Signature:

typescript

exists(): this is QueryDocumentSnapshot<AppModelType, DbModelType>;

Returns:

this is QueryDocumentSnapshot<AppModelType, DbModelType>

true if the document exists.

DocumentSnapshot.get()

Retrieves the field specified by fieldPath. Returns undefined if the document or field doesn't exist.

Signature:

typescript

get(fieldPath: string | FieldPath): any;

Parameters

Parameter	Type	Description
fieldPath	string \| FieldPath	The path (for example 'foo' or 'foo.bar') to a specific field.

Returns:

any

The data at the specified field location or undefined if no such field exists in the document.