unitport.blogg.se - Swift downcast initializer

#Swift downcast initializer code

The keyword as can be used to upcast or downcast. If that works for you, great! But I don't think it strikes the right balance between readable, concise and safe. A variable of a class may refer to an instance of its subclass or superclass.

Ps: I've had this argument before at work, someone was saying we should use guard let v = v else Variables and Constants that live in the scope of the class are referred to as instance variables. Imagine having "accessing nested view controller n✣ in navigation controller" as your error message instead of "Unexpectedly found nil while unwrapping an Optional" Initializers allow us to set the initial state of a class.

#Swift downcast initializer code

knowing where the error comes from and why it happens before even looking at the code is extremely valuable from a cognitive standpoint. Swift provides various types of initializers such as memberwise initializers, custom initializers, designated initializers, convenience initializers, required initializers, as well as optional.

when reading code it automatically help documenting the assumption that explains why we think force unwrap is necessary, no need to start thinking about the lifetime of the view or closures, it's just written there.

It's more visually striking than ! so it's easier to detect on a cursory reading of the code (typically during review or for newcomers).