The Role of Interfaces in Go

Learn how interfaces can define a common set of behaviors and allow easy code extensibility.

In Go, interfaces are one of the fundamental building blocks that allow you to increase the flexibility of your application.

Interfaces define a common set of behaviors, making it possible to introduce new types and functionality without modifying existing code.

In this article, we will explore the details of interfaces in Go and look at how they can be implemented to create customizable code structures.

Photo by Christina Morillo

What is an interface?

An interface in Go is a collection of multiple method signatures.

Each signature is composed of a method name, a set of optional parameters, and optional return values.

Both the parameters and return values are defined based on their type and order, while instead, the names are not mandatory.

However, if you set at least the name of one parameter/return value, you must also define the name of all other parameters/return values for the same signature.

type Int interface {
  Method1()
  Method2(a, b int) (err error)
  Method3(int, string, bool) error
  Method4(a int) (bool, error)
}