I recently started learning Swift, now I'm trying to safely unwrap multiple variables that come from a JSON response which might contain or not that key.
Example of the JSON response:
{
"products: [{
"foo": "foo"
"bar": "bar"
}, {
"foo": "foo"
}]
}
Here I'm trying the following:
let dataTask = URLSession.shared.dataTask(with: myURL) { (data, response, error) in
guard let safeData = data else { return }
do {
let json = try JSONSerialization.jsonObject(with: safeData, options: .mutableLeaves)
if let jsonDict = json as? [String : Any] {
let productArray = jsonDict["products"] as? [[String : Any]]
for product in productArray! {
if let foo = product["foo"] as? String, let bar = product["bar"] as? String {
let prod = Product(foo: foo, bar: bar)
products.append(prod)
}
}
}
} catch {
print ("Error: \(error)")
}
}
What I want to do is to give bar a default value (coalescing) if the value is nil, such as "Not Available" in order to display it in a label.
Is it possible? How could I do that?
You can try
let prod = Product(foo:product["foo"] as? String ?? "Not Available" , bar: product["bar"] as? String ?? "Not Available" )
struct Root: Decodable {
let products: [Product]
}
struct Product: Decodable {
let foo: String
let bar: String?
enum CodingKeys: String, CodingKey {
case foo , bar
}
init(from decoder: Decoder) throws {
let container = try decoder.container(keyedBy: CodingKeys.self)
do {
let foo = try container.decode(String.self, forKey: .foo)
let bar = try container.decodeIfPresent(String.self, forKey: .bar) ?? "Not Available"
self.init(foo:foo, bar:bar)
} catch let error {
print(error)
throw error
}
}
}
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