AnyCodable

AnyCodable.swift

public struct AnyCodable: Codable {
    public var base: Any
    
    public init(_ base: Any) {
        self.base = base
    }

    public init(from decoder: Decoder) throws {
        let container = try decoder.singleValueContainer()
        guard !container.decodeNil() else {
            throw DecodingError.valueNotFound(Any.self, .init(codingPath: decoder.codingPath, debugDescription: "Found nil"))
        }

        func decode<T: Decodable>(_: T.Type) -> (Decoder) -> Any? {
            return { try? T.init(from: $0) }
        }
        let types: [(Decoder) -> Any?] = [
            decode(String.self),
            decode(Bool.self),
            decode(Int.self),
            decode(Int8.self),
            decode(Int16.self),
            decode(Int64.self),
            decode(UInt.self),
            decode(UInt8.self),
            decode(UInt16.self),
            decode(UInt64.self),
            decode(Double.self),
            decode(Float.self),
            decode([AnyCodable].self),
            decode([String: AnyCodable].self)
        ]

        for type in types {
            if let value = type(decoder) {
                self.base = value
                return
            }
        }

        throw DecodingError.typeMismatch(Any.self, .init(codingPath: decoder.codingPath, debugDescription: "Value isn't Decodable"))
    }

    public func encode(to encoder: Encoder) throws {
        if base is NSNull {
            return
        }

        guard let value = base as? Encodable else {
            throw EncodingError.invalidValue(base, .init(codingPath: encoder.codingPath, debugDescription: "Value isn't Encodable"))
        }
        try value.encode(to: encoder)
    }
}

extension KeyedDecodingContainer {
    public func decode(_ type: [String: Any].Type, forKey key: K) throws -> [String: Any] {
        return try decode([String: AnyCodable].self, forKey: key).mapValues(\.base)
    }
}

extension KeyedEncodingContainer {
    public mutating func encode(_ value: [String: Any], forKey key: K) throws {
        try encode(value.mapValues(AnyCodable.init), forKey: key)
    }
}