Swift: shortcut unwrapping of array of optionals

Question

Assume we have an array of optionals defined:

var arrayOfOptionals: [String?] = [\"Seems\", \"like\", \"an\", nil, \"of\", \"optionals\"]

I

Answer 1

The more interesting, how to unwrap an optional array of optional values. It is important to deal when we are working with JSON, because JSON can potentially contain null value for an array of something.

Example:

{ "list": null }
// or
{ "list": [null, "hello"] }

To fill a Swift struct we may have a model:

struct MyStruct: Codable {
    var list: [String?]?
}

And to avoid working with String?? as a first item we could:

var myStruct = try! JSONDecoder.init().decode(MyStruct.self, from: json.data(using: .utf8)!)
let firstItem: String? = s1.list?.compactMap { $0 }.first

With compactMap { $0 } we can avoid

let i2: String?? = s1.list?.first

compactMap { $0 } is an equivalent of filter { $0 != nil }. map { $0! }