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:
export declare class DocumentSnapshot<AppModelType = DocumentData, DbModelType extends DocumentData = DocumentData>
Constructors
| Constructor | Modifiers | Description |
|---|---|---|
| (constructor)() | Constructs a new instance of the DocumentSnapshot class |
Properties
| Property | Modifiers | Type | Description |
|---|---|---|---|
| id | string | Property of the DocumentSnapshot that provides the document's ID. |
|
| metadata | SnapshotMetadata | Metadata about the DocumentSnapshot, including information about its source and local modifications. |
|
| ref | DocumentReference<AppModelType, DbModelType> | The DocumentReference for the document included in the DocumentSnapshot. |
Methods
| Method | Modifiers | Description |
|---|---|---|
| data(options) | Retrieves all fields in the document as an Object. Returns undefined if the document doesn't exist.By default, serverTimestamp() values that have not yet been set to their final value will be returned as null. You can override this by passing an options object. |
|
| exists() | Returns whether or not the data exists. True if the document exists. | |
| get(fieldPath, options) | Retrieves the field specified by fieldPath. Returns undefined if the document or field doesn't exist.By default, a serverTimestamp() that has not yet been set to its final value will be returned as null. You can override this by passing an options object. |
DocumentSnapshot.(constructor)
Constructs a new instance of the DocumentSnapshot class
Signature:
protected constructor();
DocumentSnapshot.id
Property of the DocumentSnapshot that provides the document's ID.
Signature:
get id(): string;
DocumentSnapshot.metadata
Metadata about the DocumentSnapshot, including information about its source and local modifications.
Signature:
readonly metadata: SnapshotMetadata;
DocumentSnapshot.ref
The DocumentReference for the document included in the DocumentSnapshot.
Signature:
get ref(): DocumentReference<AppModelType, DbModelType>;
DocumentSnapshot.data()
Retrieves all fields in the document as an Object. Returns undefined if the document doesn't exist.
By default, serverTimestamp() values that have not yet been set to their final value will be returned as null. You can override this by passing an options object.
Signature:
data(options?: SnapshotOptions): AppModelType | undefined;
Parameters
| Parameter | Type | Description |
|---|---|---|
| options | SnapshotOptions | An options object to configure how data is retrieved from the snapshot (for example the desired behavior for server timestamps that have not yet been set to their final value). |
Returns:
AppModelType | undefined
An Object containing all fields in the document or undefined if the document doesn't exist.
DocumentSnapshot.exists()
Returns whether or not the data exists. True if the document exists.
Signature:
exists(): this is QueryDocumentSnapshot<AppModelType, DbModelType>;
Returns:
this is QueryDocumentSnapshot<AppModelType, DbModelType>
DocumentSnapshot.get()
Retrieves the field specified by fieldPath. Returns undefined if the document or field doesn't exist.
By default, a serverTimestamp() that has not yet been set to its final value will be returned as null. You can override this by passing an options object.
Signature:
get(fieldPath: string | FieldPath, options?: SnapshotOptions): any;
Parameters
| Parameter | Type | Description |
|---|---|---|
| fieldPath | string | FieldPath | The path (for example 'foo' or 'foo.bar') to a specific field. |
| options | SnapshotOptions | An options object to configure how the field is retrieved from the snapshot (for example the desired behavior for server timestamps that have not yet been set to their final value). |
Returns:
any
The data at the specified field location or undefined if no such field exists in the document.