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 |
