I am attempting to load race data into my application, and I'm using Loading a specific kind of Codable data as my guide.

I've taken a CSV and converted it to JSON using an online tool.

Here's my struct for holding each individual race result:

struct IndividualResult: Codable, Identifiable {
    let place: Int
    let name: String
    let city: String
    let id: Int
    let age: Int
    let agePlace: Int
    let chipTime: String
    let gunTime: String
    let totalPace: String
}

And my bundle extension to load and decode the JSON. I've modified this to return a simple array of IndividualResult, instead of a dictonary in the example. I wonder if this is part of my problem.

extension Bundle {
    func decode(_ file: String) -> [IndividualResult] {
        guard let url = self.url(forResource: file, withExtension: nil) else {
            fatalError("Failed to locate \(file) in bundle.")
        }

        guard let data = try? Data(contentsOf: url) else {
            fatalError("Failed to load \(file) from bundle.")
        }

        let decoder = JSONDecoder()

        guard let loaded = try? decoder.decode([IndividualResult].self, from: data) else {
            fatalError("Failed to decode \(file) from bundle.")
        }

        return loaded
    }
}

Here's my JSON: https://pastebin.com/QXngvmbS

When I run my application and try to load the JSON, I get this error: Fatal error: Failed to decode results.json from bundle.

I've compared my JSON to my struct and I think they match. Am I misunderstanding that my JSON represents and array? Could the '/' character in the totalPlace string cause an issue?

Change this:

guard let loaded = try? decoder.decode([IndividualResult].self, from: data) else {
    fatalError("Failed to decode \(file) from bundle.")
}

return loaded

to this:

do {
    let loaded = try decoder.decode([IndividualResult].self, from: data)
    return loaded
} catch {
    print(error)
    fatalError()
}

and see what the actual error you are getting back is.

Ah ha! That made finding the error easier!

valueNotFound(Swift.Int, Swift.DecodingError.Context(codingPath: [_JSONKey(stringValue: "Index 118", intValue: 118), CodingKeys(stringValue: "age", intValue: nil)], debugDescription: "Expected Int value but found null instead.", underlyingError: nil))
raceresults/Bundle-Decodable.swift:27: Fatal error
2023-03-13 14:25:03.305494-0700 raceresults[5396:17657257] raceresults/Bundle-Decodable.swift:27: Fatal error

The 119th object has null as it's value.

 {
   "place": 119,
   "name": "Unknown Partic. 3120",
   "city": "",
   "id": 3120,
   "age": null,
   "agePlace": 1,
   "chipTime": "1:02:26",
   "gunTime": "1:02:26",
   "totalPace": "12:35/M"
 },

What's the best strategy to deal with these errors? I'd like to handle it gracefully if possible, as I won't be able to guarantee the data is clean. (Thought I may just clean it up to move on as this is a test/demo and not a real app.)

Hi, I was able to get a result using the code below:

// MARK: - ResultElement
struct ResultElement: Codable {
    let place: Int
    let name: String
    let city: String
    let id: Int
    let age: Int?
    let agePlace: Int
    let chipTime: String
    let gunTime: String
    let totalPace: String
}

typealias Result = [ResultElement]

extension Bundle {
    func decode(_ file: String) -> Result {
        guard let url = self.url(forResource: file, withExtension: nil) else {
            fatalError("Failed to locate \(file) in bundle.")
        }

        guard let data = try? Data(contentsOf: url) else {
            fatalError("Failed to load \(file) from bundle.")
        }

        let decoder = JSONDecoder()

        guard let loaded = try? decoder.decode(Result.self, from: data) else {
            fatalError("Failed to decode \(file) from bundle.")
        }

        return loaded
    }
}

I think is the optional in the age property because there is a racer who's age is null.

typealias Result = [ResultElement]

Not a good idea to call this Result, since there is a built-in Result type that you will conflict with by doing so.

Since this is an array (i.e., more than one) of ResultElements, it should be called Results instead.