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iOS Error Handling in Swift Error Handling Handling Errors

Posted by joelbumpus
joelbumpus
3,354 Points

Stuck and need help, please.

What am I missing or have incorrect here in my code?

error.swift 
enum ParserError: ErrorType {
    case EmptyDictionary
    case InvalidKey
}

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

        func parse() throws {

            guard (data?["someKey"]) != nil  else {
        throw ParserError.invalidKey
    }

    guard (data?.keys) != nil else {
        throw ParserError.emptyDictionary
    }
}
let data: [String : String?]? = ["someKey": nil]

do {
    let parser = try Parser(data: data).parse()
} catch {
    print("Error")
}

2 Answers

Jeff McDivitt
Jeff McDivitt
23,970 Points
Jeff McDivitt
Jeff McDivitt
23,970 Points

Hi Joel -

You are very close. I did task 1 differently but I believe you way will work. I believe you will see what you are missing by taking a look at the code below

enum ParserError: Error {
    case emptyDictionary
    case invalidKey
}

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

    func parse() throws {

        guard let data = data else {
            throw ParserError.emptyDictionary
        }

        guard data["somekey"] != nil else {
            throw ParserError.invalidKey


        }
    }
}

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

do {
    let parser = try Parser(data: data)
    try parser.parse()
} catch ParserError.emptyDictionary(let description) {
    print(description)
}
catch ParserError.invalidKey(let description) {
    print(description)
}
joelbumpus
joelbumpus
3,354 Points
joelbumpus
joelbumpus
3,354 Points

Jeff, this worked perfectly. Thank you for the explanation and clarity here!