There is no way to do this out of the box, since there's no 1-1 mapping between properties of a Codable
type and its coding keys, since there might be properties that aren't part of the encoded model or properties that depend on several encoded keys.
However, you should be able to achieve your goals by defining a mapping between the properties and their coding keys. You were on the right track with KeyPath
s, you just need to define a function that takes a KeyPath
whose root type is your codable model and return the coding key from said function.
struct MyCodable: Codable {
let id: Int
let name: String
// This property isn't part of the JSON
var description: String {
"\(id) \(name)"
}
enum CodingKeys: String, CodingKey {
case name = "Name"
case id = "identifier"
}
static func codingKey<Value>(for keyPath: KeyPath<MyCodable, Value>) -> String? {
let codingKey: CodingKeys
switch keyPath {
case \MyCodable.id:
codingKey = .id
case \MyCodable.name:
codingKey = .name
default: // handle properties that aren't encoded
return nil
}
return codingKey.rawValue
}
}
MyCodable.codingKey(for: \.id)