Firestore崩溃 [英] Crashes with Firestore

问题描述

当我查询集合中不存在的文档时，我仍然返回一个非null对象，当我尝试调用 documentSnapshot?.data()时，该对象会崩溃./p>

返回的错误是"Document'< FSTDocumentKey:XXXXXX>'不存在.请在调用document.data之前检查document.exists以确保该文档存在.'"

解决方案

我发现可以用一个漂亮的小警卫声明来解决这个问题:

  guard(documentSnap?.exists ?? false)，错误== nil else {return} 

以下是此检查的有效示例:

  func getUserData(uid:字符串，完成:@escaping(([[String:Any] ?, Error?))->()){让document = defaultStore.collection("user-data").document(uid)document.getDocument {(documentSnap，error)在保护(documentSnap?.exists ?? false)，错误== nil else {完成((nil，错误))返回}完成((documentSnap?.data()，错误))}} 

我不知道为什么您必须调用 .exists()，文档不仅是nil，而且还是学习曲线的一部分，还是Beta版的产物SDK

When I query a collection for a document that doesn't exist, I'm still returned a non-nil object, which crashes when I try to call documentSnapshot?.data().

The error returned is "Document '<FSTDocumentKey: XXXXXX>' doesn't exist. Check document.exists to make sure the document exists before calling document.data.'"

解决方案

I've found this can be solved with a nifty little guard statement:

guard (documentSnap?.exists ?? false), error == nil else { return }

Here's a working example of this check:

func getUserData(uid: String, completion: @escaping(([String: Any]?, Error?)) -> ()) {

        let document = defaultStore.collection("user-data").document(uid)

        document.getDocument { (documentSnap, error) in

            guard (documentSnap?.exists ?? false), error == nil else {
                completion((nil, error))
                return
            }

            completion((documentSnap?.data(), error))
}}

I don't know why you have to call .exists(), and the document isn't just nil, but this is either part of the learning curve, or an artifact of a Beta SDK

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