A DocumentSnapshot is an immutable representation for a document in a Firestore database. The data can be extracted with [data()] or [get(fieldPath)] 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] property to explicitly verify a document's existence.
DocumentSnapshot
Package
@google-cloud/firestoreConstructors
(constructor)(ref, _fieldsProto, readTime, createTime, updateTime)
constructor(ref: DocumentReference<T>,
_fieldsProto?: ApiMapValue | undefined, readTime?: Timestamp, createTime?: Timestamp, updateTime?: Timestamp);
Constructs a new instance of the DocumentSnapshot
class
Name | Description |
ref |
DocumentReference<T>
The reference to the document. |
_fieldsProto |
ApiMapValue | undefined
The fields of the Firestore |
readTime |
Timestamp
The time when this snapshot was read (or undefined if the document exists only locally). |
createTime |
Timestamp
The time when the document was created (or undefined if the document does not exist). |
updateTime |
Timestamp
The time when the document was last updated (or undefined if the document does not exist). |
Properties
_fieldsProto
readonly _fieldsProto?: ApiMapValue | undefined;
createTime
get createTime(): Timestamp | undefined;
The time the document was created. Undefined for documents that don't exist.
{Timestamp|undefined} DocumentSnapshot#createTime
let documentRef = firestore.doc('col/doc');
documentRef.get().then(documentSnapshot => {
if (documentSnapshot.exists) {
let createTime = documentSnapshot.createTime;
console.log(`Document created at '${createTime.toDate()}'`);
}
});
exists
get exists(): boolean;
True if the document exists.
{boolean} DocumentSnapshot#exists
let documentRef = firestore.doc('col/doc');
documentRef.get().then((documentSnapshot) => {
if (documentSnapshot.exists) {
console.log(`Data: ${JSON.stringify(documentSnapshot.data())}`);
}
});
id
get id(): string;
The ID of the document for which this DocumentSnapshot contains data.
{string} DocumentSnapshot#id
let documentRef = firestore.doc('col/doc');
documentRef.get().then((documentSnapshot) => {
if (documentSnapshot.exists) {
console.log(`Document found with name '${documentSnapshot.id}'`);
}
});
readTime
get readTime(): Timestamp;
The time this snapshot was read.
{Timestamp} DocumentSnapshot#readTime
let documentRef = firestore.doc('col/doc');
documentRef.get().then(documentSnapshot => {
let readTime = documentSnapshot.readTime;
console.log(`Document read at '${readTime.toDate()}'`);
});
ref
get ref(): DocumentReference<T>;
A [DocumentReference]DocumentReference for the document stored in this snapshot.
{DocumentReference} DocumentSnapshot#ref
let documentRef = firestore.doc('col/doc');
documentRef.get().then((documentSnapshot) => {
if (documentSnapshot.exists) {
console.log(`Found document at '${documentSnapshot.ref.path}'`);
}
});
updateTime
get updateTime(): Timestamp | undefined;
The time the document was last updated (at the time the snapshot was generated). Undefined for documents that don't exist.
{Timestamp|undefined} DocumentSnapshot#updateTime
let documentRef = firestore.doc('col/doc');
documentRef.get().then(documentSnapshot => {
if (documentSnapshot.exists) {
let updateTime = documentSnapshot.updateTime;
console.log(`Document updated at '${updateTime.toDate()}'`);
}
});
Methods
data()
data(): T | undefined;
Retrieves all fields in the document as an object. Returns 'undefined' if the document doesn't exist.
Type | Description |
T | undefined | {T|undefined} An object containing all fields in the document or 'undefined' if the document doesn't exist. |
let documentRef = firestore.doc('col/doc');
documentRef.get().then(documentSnapshot => {
let data = documentSnapshot.data();
console.log(`Retrieved data: ${JSON.stringify(data)}`);
});
get(field)
get(field: string | FieldPath): any;
Retrieves the field specified by field
.
Name | Description |
field |
string | FieldPath
The field path (e.g. 'foo' or 'foo.bar') to a specific field. |
Type | Description |
any | {*} The data at the specified field location or undefined if no such field exists. |
let documentRef = firestore.doc('col/doc');
documentRef.set({ a: { b: 'c' }}).then(() => {
return documentRef.get();
}).then(documentSnapshot => {
let field = documentSnapshot.get('a.b');
console.log(`Retrieved field value: ${field}`);
});
isEqual(other)
isEqual(other: firestore.DocumentSnapshot<T>): boolean;
Returns true if the document's data and path in this DocumentSnapshot
is equal to the provided value.
Name | Description |
other |
FirebaseFirestore.DocumentSnapshot<T>
The value to compare against. {boolean} true if this |
Type | Description |
boolean |