Swift-如何检查Firestore文件是否存在？

Question

How do I check if a Google Firebase Firestore document exists?

I've tried the following code in my project:

let db = Firestore.firestore()
let UserName = UserNameText.text
print(UserName!)
let userRef = db.collection("users").document(UserName!)
    print("one")
    userRef.getDocument { (document, error) in
        print("two")
        if let document = document {
            print("three")
            if document.exists{
                print("Document data: \(String(describing: document.data()))")
            } else {
                print("Document does not exist")
            }
        }
    }

Here is a picture of my data on firebase.google.com: Click here

The print(UserName!) will return the correct value. The following code will output one and two but will stop there.

Answer 1

@JRLtechwriting solved my problem.

"Use if let document = document, document.exists {. Check out the example here: https://firebase.google.com/docs/firestore/query-data/get-data#get_a_document "