Swift Initialize Struct with optional stored properties

Question

I\'m a Swift newbie and I\'m trying to get my head around using Structs with optional properties. I\'ve done quite a bit of searching and got something that works but it fee

Answer 1

One approach that you can borrow from other OOP languages is parameter builder pattern. Start with a static method that returns a builder, then add methods for individual parameters, and finally call build():

let bakery = Business
    .withName("Black Forest")
    .andWebSite("www.blackforest.com")
    .andAddress("1 Main St, Springfield, IA 98765")
    .build()

Here is a skeletal implementation that enables this kind of an API:

class Business {
    // Users never call this init, it's for the builder to use
    init(name: String, webSite: String?, address: String?) {
        ...
    }
    // Here is the method the users call:
    static func withName(name: String) {
        return BusinessBuilder(name)
    }
    // This class collects parameters before calling init
    class BusinessBuilder {
        var name : String
        var webSite : String?
        var address: String?
        func andAddress(address: String) -> BusinessBuilder {
            self.address = address
            return self
        }
        func andWebSite(webSite: String) -> BusinessBuilder {
            self.webSite = webSite
            return self
        }
        func build() -> Business {
            return Business(name, webSite, address)
        }
        init(name: String) {
            self.name = name
        }
    }
}

This lets you pass as few or as many initializer parameters as you see fit, in any order that you find convenient in a given situation.

The main use of this approach is when you do not know which parameters you are going to get, for example, when they come from an XML or a database. You can call andXyz methods in a loop, and then call build() when you have no other attributes to set.

Answer 2

hope this could help you

 struct Business {
    let name : String
    var web : String?
    var address: String?


// you also need use question mark in init progress
init(name: String, web: String?, address: String?) {
    self.name = name
    self.web = web
    self.address = address
    }
}

Once you create a object you could use nil on your optional value For example :

var newBusiness = Business(name: "AWS", web: nil, address: nil)   

Answer 3

Use default values:

init(busName: String, website: String? = nil, address: String? = nil) {
    self.name = busName
    self.web = website
    self.address = address
}

Then you can call the init like this:

_ = Business(busName: "Foo")
_ = Business(busName: "Foo", website: "www.foo.bar")
_ = Business(busName: "Foo", address: "bar")
_ = Business(busName: "Foo", website: "www.foo.bar", address: "bar")