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.

The snapshot can point to a non-existing document in which case exists will return false. Calling data() or get(fieldPath) for such a document throws an error.

Properties

createTime

read-only

string

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) {
    console.log(`Document created at '${documentSnapshot.createTime}'`);
  }
});

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

string

The time this snapshot was read.

Example 

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

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

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

string

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) {
    console.log(`Document updated at '${documentSnapshot.updateTime}'`);
  }
});

Methods

data

data() returns DocumentData

Retrieves all fields in the document as an object.

Returns

DocumentData 

An object containing all fields in the document.

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 fieldPath.

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}`);
});