json.swift

import Foundation

let jsonString = "{\"message\": \"422 Unprocessable Entity\",\"errors\": {\"email\": [\"The email has already been taken.\"],\"mobile_number\" : [\"The mobile number has already been taken.\"]}}"

let jsonData = jsonString.data(using: .utf8)

do {
  if let jsonData = jsonData  {
    let object = try JSONSerialization.jsonObject(with: jsonData, options: []) as? [AnyHashable: Any]
  }
} catch {
  print(error)
}

This prints

Optional([AnyHashable("errors"): {
    email =     (
        "The email has already been taken."
    );
    "mobile_number" =     (
        "The mobile number has already been taken."
    );
}, AnyHashable("message"): 422 Unprocessable Entity])