Error parsing JSON in swift 4 - json

Question

I am trying to parse JSON in swift 4, but I get the following error:
Execution was interrupted, reason: EXC_BAD_INSTRUCTION
(code=EXC_I386_INVOP, subcode=0x0). The process has been left at the
point where it was interrupted, use "thread return -x" to return to
the state before expression evaluation.
This is my code:
struct Beer : Codable {
let name: String
let brewery: String
let style: String
}
let jsonResponse = [
"name": "Endeavor",
"brewery": "Saint Arnold",
"style": "ipa"
]
let jsonString = String(describing: jsonResponse)
let jsonData = jsonString.data(using: .utf8)
let decoder = JSONDecoder()
let beer = try! decoder.decode(Beer.self, from: jsonData!)
print(beer)

Answer 1

You are not creating JSON data correctly. String(describing:) does not create JSON strings. It creates a debug description of an object, which has nothing to do with JSON.
Rather than using a Dictionary it would be cleaner to create Data from a Beer object, then deserialize it again:
struct Beer : Codable {
let name: String
let brewery: String
let style: String
}
//Create a Beer
let aBeer = Beer(name: "Endeavor", brewery: "Saint Arnold", style: "ipa") //Create a Beer object
//--------------------------------------
//Serialize (dehydrate) the Beer
let encoder = JSONEncoder()
encoder.outputFormatting = .prettyPrinted
let jsonData: Data
do {
jsonData = try encoder.encode(aBeer)
} catch {
fatalError("Splat!. \(error.localizedDescription)")
}
//---------------------------------------
//print the dehydrated Beer
if let jsonText = String(data: jsonData, encoding: .utf8) {
print("JSON text = \(jsonText)")
}
//---------------------------------------
//Deserialize (rehydrate) the Beer
let decoder = JSONDecoder()
let decodedBeer = try! decoder.decode(Beer.self, from: jsonData)
print("Rehydrated beer = \(decodedBeer)")

Answer 2

First create JSON data by encoding your response and then decode it.
struct Beer : Codable {
let name: String
let brewery: String
let style: String
}
let jsonResponse = [
"name": "Endeavor",
"brewery": "Saint Arnold",
"style": "ipa"
]
let data = try? JSONSerialization.data(withJSONObject: jsonResponse,
options: .prettyPrinted)
let jsonEncoder = JSONEncoder()
let encoded = try jsonEncoder.encode(jsonResponse)
let jsonDecoder = JSONDecoder()
let beer = try jsonDecoder.decode(Beer.self, from: data!)
print(beer)