import Foundation


struct Foo: Encodable {
    var name = "baz"
    var dictionary: [Int32: String] = [3: "foo", 2: "bar"]
}


let encoder = JSONEncoder()
encoder.outputFormatting = .sortedKeys


let foo = Foo()
let result = String(data: try! encoder.encode(foo), encoding: .utf8)!


print(result)
// Outputs: {"dictionary":[3,"foo",2,"bar"],"name":"baz"}