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iOS Error Handling in Swift 2.0 Error Handling Handling Errors

Posted by Antonija Pek
Antonija Pek
5,819 Points

I can't figure out an answer

This is the code

enum ParserError: ErrorType {
    case EmptyDictionary
    case InvalidKey
}

struct Parser {
    var data: [String : String?]?

    func parse() throws {

    }
}

let data: [String : String?]? = ["someKey": nil]
let parser = Parser(data: data)

Task is: In this task, complete the body of the parse function. If the data is nil, throw the EmptyDictionary error. If the key "someKey" doesn't exist throw the InvalidKey error.

I really don't know where to start. Any help?

I have tried with

func parse() throws {
        guard let data = data else {
            throw ParserError.EmptyDictionary
        }

        guard let key = data["someKey"] else {
            throw ParserError.InvalidKey
        }
    }

and it passes but in next stage I get varius errors that are realated with this code that passed.

1 Answer

Michael Reining
Michael Reining
10,101 Points
Michael Reining
Michael Reining
10,101 Points

Hi Antonija,

Thanks for helping me with part 1 of the challenge. I can now return the favor.

Here is how I solved part 2 of the challenge.

enum ParserError: ErrorType {
  case EmptyDictionary
  case InvalidKey
}

struct Parser {
  var data: [String : String?]?

    func parse() throws {
        guard let data = data else {
            throw ParserError.EmptyDictionary
        }

        guard let key = data["somekey"] else {
            throw ParserError.InvalidKey
        }

    }
}

let data: [String : String?]? = ["someKey": nil]
let parser = Parser(data: data)

do {
    try parser.parse()
} catch {
    print("\(error)")
}

I hope that helps,

Mike

PS: Thanks to the awesome resources on Team Treehouse, I launched my first app.

Now you can practice writing Swift code directly on your iPhone :-)

Code! Learn how to program with Swift

Antonija Pek
Antonija Pek
5,819 Points

ahhh I was "do-catching" the wrong thing. Thanks!