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firebase-ios-sdk/FirebaseDatabase/Swift/Sources/Codable/DataSnapshot+ReadDecodable.swift

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1.4 KiB
Swift

/*
* Copyright 2020 Google LLC
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
import Foundation
#if SWIFT_PACKAGE
@_exported import FirebaseDatabaseInternal
#endif // SWIFT_PACKAGE
import FirebaseSharedSwift
public extension DataSnapshot {
/// Retrieves the value of a snapshot and converts it to an instance of
/// caller-specified type.
/// Throws `DecodingError.valueNotFound`
/// if the document does not exist and `T` is not an `Optional`.
///
/// See `Database.Decoder` for more details about the decoding process.
///
/// - Parameters
/// - type: The type to convert the document fields to.
/// - decoder: The decoder to use to convert the document. Defaults to use
/// default decoder.
func data<T: Decodable>(as type: T.Type,
decoder: Database.Decoder =
Database.Decoder()) throws -> T {
try decoder.decode(T.self, from: value ?? NSNull())
}
}