难以通过Firestore - Swift传递单个文档

import Firebase
import FirebaseFirestore

FirebaseApp.configure()
let db = Firestore.firestore()

let collectionRef = db.collection("collectionName")
let documentRef = collectionRef.document("documentId")

documentRef.getDocument { (document, error) in
    if let document = document, document.exists {
        let data = document.data()
        // 处理文档数据
    } else {
        print("文档不存在")
    }
}

let newData = [
    "key1": "value1",
    "key2": "value2"
]
documentRef.setData(newData) { (error) in
    if let error = error {
        print("更新文档失败：\(error)")
    } else {
        print("更新文档成功")
    }
}

documentRef.delete { (error) in
    if let error = error {
        print("删除文档失败：\(error)")
    } else {
        print("删除文档成功")
    }
}