Decoding a simple enum failed

[murad1981]

The basic usage of @Codable with enums is not explained in the docs, I couldn't find a simple example for basic type enums.

However, this led me to get stuck at this simple case:

@Codable
enum EnvironmentName: String {
    case test
    case staging
    //@CodedAs("OtherStaging")
    case otherStaging
}

@Codable
struct EnvironmentConfig {
    let name: EnvironmentName
    let backendHost: String
}

func parseConfig() {
    let jsonData = """
    {
        "name": "test",
        "backendHost": "myHost.com"
    }
    """.data(using: .utf8)!
        
        do {
            
            let decoder = JSONDecoder()
            let config = try decoder.decode(EnvironmentConfig.self, from: jsonData)
            print("The object is \(config)")
        } catch {
            print("Failed to decode JSON: \(error)")
        }
}

when calling the function parseConfig, the catch block is reached with this error:

Failed to decode JSON: typeMismatch(Swift.Dictionary<Swift.String, Any>, Swift.DecodingError.Context(codingPath: [CodingKeys(stringValue: "name", intValue: nil)], debugDescription: "Expected to decode Dictionary<String, Any> but found a string instead.", underlyingError: nil))

I couldn't find a fix for this error.

And if I the value for the name key in the provided json is "OtherStaging", should I use @CodedAs("OtherStaging") beside the case name in the enum ?

[soumyamahunt]

@murad1981 enums with raw value is not supported as outlined in docs. You can use the Swift compiler generated implementation, for your use-case.

[murad1981]

Thanks for the clarification

[Asura19]

@murad1981 Supported by ReerCodable

import ReerCodable

@Codable
enum EnvironmentName: String {
    case test
    case staging
    @CodingCase(match: .string("OtherStaging"))
    case otherStaging
}

@Codable
struct EnvironmentConfig {
    let name: EnvironmentName
    let backendHost: String
}

func parseConfig() {
    let jsonData = """
    {
        "name": "OtherStaging",
        "backendHost": "myHost.com"
    }
    """.data(using: .utf8)!
        
        do {
            
            let decoder = JSONDecoder()
            let config = try decoder.decode(EnvironmentConfig.self, from: jsonData)
            print("The object is \(config)")
        } catch {
            print("Failed to decode JSON: \(error)")
        }
}

parseConfig()

[murad1981]

@Asura19 wow ReerCodable looks promising and simpler in implemenation than MetaCodable especially in custom cases where we don't need to create custom structs or classes to satisfy HelperCoders.

[soumyamahunt]

The reason that enums with raw value wasn't supported is because I didn't see the additional usefulness that MetaCodable will provide with it's own implementation compared to the compiler generated one. However, this can be added to MetaCodable nonetheless.

@Codable
enum EnvironmentName: String {
    case test
    case staging
    @CodedAs("OtherStaging")
    case otherStaging
}

@Codable
struct EnvironmentConfig {
    let name: EnvironmentName
    let backendHost: String
}

func parseConfig() {
    let jsonData = """
    {
        "name": "test",
        "backendHost": "myHost.com"
    }
    """.data(using: .utf8)!
        
        do {
            
            let decoder = JSONDecoder()
            let config = try decoder.decode(EnvironmentConfig.self, from: jsonData)
            print("The object is \(config)")
        } catch {
            print("Failed to decode JSON: \(error)")
        }
}