如何使用Swift 5保存Firebase快照中的数据？

import Firebase

// 配置Firestore
let db = Firestore.firestore()

// 监听特定集合的数据变化
db.collection("yourCollectionName").addSnapshotListener { querySnapshot, error in
    guard let documents = querySnapshot?.documents else {
        print("Error fetching documents: \(error!)")
        return
    }

    let data = documents.map { $0.data() }
    // 处理数据...
}

// 假设data是一个字典，包含了你想要保存的数据
let dataToSave = ["key1": "value1", "key2": "value2"]

// 将数据转换为JSON字符串
if let jsonData = try? JSONSerialization.data(withJSONObject: dataToSave, options: []),
   let jsonString = String(data: jsonData, encoding: .utf8) {

    // 保存到UserDefaults
    UserDefaults.standard.set(jsonString, forKey: "yourDataKey")
}

// 从UserDefaults加载数据
if let savedData = UserDefaults.standard.string(forKey: "yourDataKey"),
   let dataFromString = savedData.data(using: .utf8),
   let loadedData = try? JSONSerialization.jsonObject(with: dataFromString, options: []) as? [String: Any] {

    // 使用loadedData...
}