DocumentSnapshot

class

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.

Properties

createTime

read-only

(Timestamp or undefined)

The time the document was created. Undefined for documents that don't exist.

Example 

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

read-only

boolean

True if the document exists.

Example 

let documentRef = firestore.doc('col/doc');

documentRef.get().then((documentSnapshot) => {
  if (documentSnapshot.exists) {
    console.log(`Data: ${JSON.stringify(documentSnapshot.data())}`);
  }
});

id

read-only

string

The ID of the document for which this DocumentSnapshot contains data.

Example 

let documentRef = firestore.doc('col/doc');

documentRef.get().then((documentSnapshot) => {
  if (documentSnapshot.exists) {
    console.log(`Document found with name '${documentSnapshot.id}'`);
  }
});

readTime

read-only

Timestamp

The time this snapshot was read.

Example 

let documentRef = firestore.doc('col/doc');

documentRef.get().then(documentSnapshot => {
  let readTime = documentSnapshot.readTime;
  console.log(`Document read at '${readTime.toDate()}'`);
});

ref

read-only

DocumentReference

A DocumentReference for the document stored in this snapshot.

Example 

let documentRef = firestore.doc('col/doc');

documentRef.get().then((documentSnapshot) => {
  if (documentSnapshot.exists) {
    console.log(`Found document at '${documentSnapshot.ref.path}'`);
  }
});

updateTime

read-only

(Timestamp or undefined)

The time the document was last updated (at the time the snapshot was generated). Undefined for documents that don't exist.

Example 

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() returns (DocumentData or undefined)

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

Returns

(DocumentData or undefined) 

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

Example 

let documentRef = firestore.doc('col/doc');

documentRef.get().then(documentSnapshot => {
  let data = documentSnapshot.data();
  console.log(`Retrieved data: ${JSON.stringify(data)}`);
});

get

get(field) returns any type

Retrieves the field specified by field.

Parameter

field

(string or FieldPath)

The field path (e.g. 'foo' or 'foo.bar') to a specific field.
Returns

any type 

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

Example 

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

isEqual(other) returns boolean

Returns true if the document's data and path in this DocumentSnapshot is equal to the provided value.

Parameter

other

any type

The value to compare against.
Returns

boolean 

true if this DocumentSnapshot is equal to the provided value.