Hands-On Swift 5 Microservices Development

Using generic functions

A generic function is one that can take multiple types and work with them equally. Especially in server applications, where you deal with a lot of data, this becomes very handy. Instead of writing a function for each type of information, you can write it once and use it for every type.

Let's look at an example:

function saveModel<T:Model>(_ model: T, on app: Application) -> EventLoopFuture<T> {    return model.save(on: app).transform(to: model)}

You can see that the function is using a generic type T that we call model in the signature of the function. We are also defining that this type has to implement Model.

Now, whenever we want to save a class that conforms to Model, we can do so as follows:

let user = User()return ...