Swift: Reducing the length of Init methods - swift

Question

I would like to reduce the length of init method.
struct Person {
var id: Int
var firstName: String
var lastName: String
var vehicle: String
var location: String
var timeZone: String
init (id: Int, firstName: String, lastName: String, vehicle: String, location: String, timeZone: String ) {
self.firstName = firstName
self.lastName = lastName
self.vehicle = vehicle
self.location = location
self.timeZone = timeZone
}
}
Below is an instance of Person I am creating. I have to pass in the value of every single variable inline.
let person = Person(id: 22, firstName: "John", lastName: "Doe", vehicle: "Chevy", location: "Dallas", timeZone: "CST")
Question: How can I shrink the length of init? In Obj-C I used to create a data model class. Populate it's variables and then pass the entire class, reducing the length of the init method.
i.e.
Person *person = [Person new];
person.id = 22;
person.firstName = "John";
person.lastName = "Doe";
person.vehicle = "Chevy";
person.location = "Dallas";
person.timeZone = "CST"
Person *person = [Person initWithPerson:person];
What's an equivalent way in Swift to reduce the length of init without having to initialize every single variable inline? I know tuples is one way, is there any other best practice?

Answer 1

Just remove the initializer!
struct Person {
let id: Int
let firstName: String
let lastName: String
let vehicle: String
let location: String
let timeZone: String
}
Now you can use the memberwise initializer
Person(
id: 87112,
firstName: "Walter",
lastName: "White",
vehicle: "2004 Pontiac Aztek",
location: "Albuquerque",
timeZone: "UTC-07:00"
)
Structure types automatically receive a memberwise initializer if they do not define any of their own custom initialisers.
The Swift Programming Language
DO NOT use var
As you can see I replaced var with let.
Unless you need to change some properties of a Person after the value has been created, I suggest you to use let. Otherwise you are free to use var. This way the compiler will prevent unwanted changes.
DO NOT use Optionals
I don't know the business logic of your app, however if a Person must have all that 6 properties always populated, don't make them optionals. Otherwise every time you need to use a Person value the compiler will force you to check if that optional has a value.
DO NOT use Implicitly Unwrapped Optionals
Seriously. There are a few cases where they are useful and a model value is not one of them

Answer 2

Using a struct you actually don't need an initializer
struct Person {
var id : Int?
var firstName: String?
var lastName: String?
var vehicle: String?
var location: String?
var timeZone: String?
}
var person = Person()
person.id = 22
person.firstName = "John"
person.lastName = "Doe"
person.vehicle = "Chevy"
person.location = "Dallas"
person.timeZone = "CST"
You can do the same with non-optionals
struct Person {
var id = 0
var firstName = ""
var lastName = ""
var vehicle = ""
var location = ""
var timeZone = ""
}
Consider also the benefit of an initializer to declare (read-only) constants
struct Person {
let id : Int
let firstName : String
let lastName : String
let vehicle : String
let location : String
let timeZone : String
}
In this case you have to use the implicit memberwise initializer.
let person = Person(id: 22, firstName: "John", lastName: "Doe", vehicle: "Chevy", location: "Dallas", timeZone: "CST")

Answer 3

Like it was mentioned in the comments, an initializer will be created for you, and it'll look like this:
Person(id: Int?, firstName: String?, lastName: String?, vehicle: String?, location: String?, timeZone: String?)
However, you can also do this:
var person = Person()
person.id = 100
person.firstName = "Name"
...
Like you used to do in ObjC. Note that person was declared as var, because if it was declared as let, you wouldn't be able to mutate it.