Go Interfaces

What is an Interface in Go?

In Go, an interface is a type that defines a contract of methods. Any type that implements these methods satisfies the interface, making Go's implementation of interfaces implicit. This means that you do not need to explicitly declare that a type implements an interface.

Interfaces are a powerful feature in Go, allowing developers to write flexible and reusable code. They enable polymorphism in Go, where a single function can operate on different types as long as they implement the same interface.

Defining an Interface

To define an interface in Go, you use the type keyword followed by the interface name and the keyword interface. Inside the interface block, you define the method signatures that the interface requires.

Implementing an Interface

To implement an interface in Go, a type must provide definitions for all the methods declared in the interface. Go does not require an explicit declaration that a type implements an interface; it is done implicitly by simply defining the required methods.

Using Interfaces

Once a type implements an interface, you can use it like the interface type. This allows you to write functions that can operate on any type implementing the interface.

Type Assertions and Type Switches

Sometimes you need to access the underlying type of an interface. Go provides type assertions and type switches for this purpose. Type assertions allow you to extract the underlying concrete type from the interface.

Type switches are a more powerful tool that let you perform operations based on the dynamic type of an interface.