Enums Static Members Explained in Swift

An enum with static members can be an incredibly useful way to logically group constants or manage configuration values.

Here’s an example!

enum API {
    
    static let baseURL = "https://api.myexampleapi.com"
    
    enum Endpoint {
        static let login = "/user/login"
        static let signup = "/user/signup"
        static let profile = "/user/profile"
    }
}

let url = URL(string: API.baseURL + API.Endpoint.login)
print(url!) // result: https://api.myexampleapi.com/user/login
        

In this code, the API enum has a static member that’s a constant named baseURL.

Then it has a nested enum named Endpoint, which has three static constant members named login, signup and profile.

Next, URL(string:) initializes a URL instance from the provided string. Here, it creates a URL from the values stored in the API enum and stores the resulting string in the constant named url.

Note: URL(string:) is an Optional that returns nil if the string doesn’t represent a valid URL.

Finally, we unwrap the Optional url and print it.

This approach to using enums is beneficial because it allows for logical grouping of API-related constants, while the nested Endpoint adds further categorisation, helping to keep the code organised and clean.