Can't check if document exists in cloud firestore database and with reactjs

Question

I was doing a simple project when I encountered a problem in the firestore database code, When I check if a document exists it only returns true but never false event when it should do

My Code:

    db.collection("Users")
            .where("email", "==", state.email_value).get()
            .then(function(querySnapshot) {
                querySnapshot.forEach(function(doc) {
                    if(doc.exists) {
                        console.log("Document Exist");
                    } else {
                        console.log("Document Doesn't Exist);
                    }
                });
            });

The Code only executes when the condition is true but not false. I even tried outputing the doc.exists value but it only outputs when its true

Answer 1

If there are no documents, the querySnapshot.forEach(function(doc)... will never be entered.

You'll want to instead check if the query itself has results:

db.collection("Users")
        .where("email", "==", state.email_value).get()
        .then(function(querySnapshot) {
            if (!querySnapshot.empty) {
                console.log("Document Exist");
            }
            else {
                console.log("Document Doesn't Exist");
            }
        });

For situations like this, I highly recommend keeping the reference documentation of Firebase handy: https://firebase.google.com/docs/reference/js/firebase.firestore.QuerySnapshot