What is the empty interface

The empty interface interface{} (or any in Go 1.18+) is a type that matches every value in Go because it declares no methods. It allows you to store values of any type in a single variable, slice, or map without knowing their specific type at compile time.

var x interface{} = 42
x = "hello"
x = []int{1, 2, 3}

Use it when you need a generic container, but remember you must use type assertions or type switches to access the underlying value's specific methods or fields.

The empty interface is a universal container that can hold any data type, like a box that fits anything you put inside it. It is useful when writing functions that need to accept different kinds of inputs without defining a specific type for each one. However, you must check what type of data is inside before you can use it.