DocumentSnapshot

DocumentSnapshot

new DocumentSnapshot()

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.

Members

createTime

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

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

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

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

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

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() → {T|undefined}

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

Returns:
Type Description
T | 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(field) → {*}

Retrieves the field specified by field.

Parameters:
Name Type Description
field string | FieldPath

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

Returns:
Type Description
*

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(other) → {boolean}

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

Parameters:
Name Type Description
other *

The value to compare against.

Returns:
Type Description
boolean

true if this DocumentSnapshot is equal to the provided value.