In the Swift programming language, certain concepts may appear daunting at first but hold immense power once understood. Generics is one of those concepts. Today, we will simplify their purpose and explore the elegance and versatility of generics. By the end, you’ll have a better understanding of generics and how to squeeze the most out of them.

The Overlooked Potential of Generics

Generics are often underutilized or misunderstood by developers. However, they offer a powerful way to write flexible and reusable code. Whether you’re working with collections, algorithms, or network services, generics can streamline your code and make it more adaptable to different types.

The Essence of Generics

At its core, generics allow us to write functions, classes, and structures that can work with any type (known as polymorphism). Rather than specifying the type of data a function or data structure will take in as part of the signature, we use placeholders, or type parameters, to indicate that the code should operate on any type. Or any type that conforms to a protocol. Multiple protocols are also allowed: func printDescriptions<T: Printable & LargeShape>(items: [T], minArea: Double) {}. This flexibility enables us to write more generic, yet still type-safe, code because Swift generics provide stronger type safety because the compiler enforces type constraints at compile time. This helps catch type-related errors early in the development.

Visualizing the Problem

Let’s consider a scenario where you have four identical types that represent the rounds in a poker hand: preflop, flop, turn, and river. The behavior is identical for each, so we create a protocol which each will conform to.

protocol Round {
  var openingPot: Int { get }
  var closingPot: Int { get }
  var players: [Players] { get }
  var round: String { get }

Now, our types will conform as such:

struct Preflop: Round {}
struct Flop: Round {}
struct Turn: Round {}
struct River: Round {}
The Generic Approach

Here’s a concise implementation of a generic function that accepts any of the 4 types:

func prepareTablePositions<T: Round>(_ round: T) {}

You could have just used the protocol:

func prepareTablePositions(_ round: Round) {}

But, you’ll miss out on:

  1. Flexibility: With generics, you can specify a specific type when calling the function (printDescriptions(items: shapes2)), allowing you to work with arrays of specific types rather than generic protocols.
  2. Type Safety: Generics provide stronger type safety because the compiler enforces type constraints at compile time. This helps catch type-related errors early in the development process.
  3. Code Reusability: Generics promotes code reusability by allowing functions and types to work with a wide range of types, reducing the need for duplication or specialized implementations.

Understanding Flexibility

With generics, we can write functions, structures, and classes that operate on a wide range of types while still ensuring type safety at compile time. This enables us to write cleaner, more concise code that is less prone to errors.


In this exploration, we’ve delved into some of the nuances of generics in Swift. By understanding the essence of generics, visualizing the problem, and embracing the generic approach, you now have the tools to harness the power of generics in your own code.

That’s all for now, fellow developers! I hope this post has shed light on the beauty of generics in Swift. If you have any questions or insights to share, feel free to leave a comment below. And don’t forget to connect with me on LinkedIn and Twitter for more insights and future posts. Happy coding!