doc method
Gets a DocumentReference for the document within the collection
at the specified path. If no documentPath
is specified,
an automatically-generated unique ID will be used for the
returned DocumentReference.
The optional documentPath
parameter is a slash-separated path to
a document.
Returns non-null DocumentReference.
Implementation
DocumentReference doc([String? documentPath]) {
final jsObjectDoc =
(documentPath != null) ? jsObject.doc(documentPath) : jsObject.doc();
return DocumentReference.getInstance(jsObjectDoc);
}