Firebase Cloud Firestore create entry or update if it already exists
What you're looking for is the merge option in the set operation. From the documentation on setting a document:
var cityRef = db.collection('cities').doc('BJ'); var setWithMerge = cityRef.set({ capital: true }, { merge: true });If you're not sure whether the document exists, pass the option to merge the new data with any existing document to avoid overwriting entire documents.