What's the best way to check if a Firestore record exists if its path is known?

Question

Given a given Firestore path what's the easiest and most elegant way to check if that record exists or not short of creating a document observable and subscribing to it?

Answer 1

Taking a look at this question it looks like .exists can still be used just like with the standard Firebase database. Additionally, you can find some more people talking about this issue on github here

The documentation states

NEW EXAMPLE

var docRef = db.collection("cities").doc("SF");  docRef.get().then((doc) => {     if (doc.exists) {         console.log("Document data:", doc.data());     } else {         // doc.data() will be undefined in this case         console.log("No such document!");     } }).catch((error) => {     console.log("Error getting document:", error); }); 

OLD EXAMPLE

const cityRef = db.collection('cities').doc('SF'); const doc = await cityRef.get();      if (!doc.exists) {     console.log('No such document!'); } else {     console.log('Document data:', doc.data()); } 

Note: If there is no document at the location referenced by docRef, the resulting document will be empty and calling exists on it will return false.

OLD EXAMPLE 2

var cityRef = db.collection('cities').doc('SF');  var getDoc = cityRef.get()     .then(doc => {         if (!doc.exists) {             console.log('No such document!');         } else {             console.log('Document data:', doc.data());         }     })     .catch(err => {         console.log('Error getting document', err);     }); 

Answer 2

If the model contains too much fields, would be a better idea to apply a field mask on the CollectionReference::get() result (let's save more google cloud traffic plan, \o/). So would be a good idea choose to use the CollectionReference::select() + CollectionReference::where() to select only what we want to get from the firestore.

Supposing we have the same collection schema as firestore cities example, but with an id field in our doc with the same value of the doc::id. Then you can do:

var docRef = db.collection("cities").select("id").where("id", "==", "SF");  docRef.get().then(function(doc) {     if (!doc.empty) {         console.log("Document data:", doc[0].data());     } else {         console.log("No such document!");     } }).catch(function(error) {     console.log("Error getting document:", error); }); 

Now we download just the city::id instead of download entire doc just to check if it exists.