Kotlin companion objects
A companion object is similar in syntax to an inner class because we declare it inside a regular class, but note we refer to it as an object, not a class. This implies it is in itself an instance as opposed to a blueprint for an instance. This is exactly what it is. When we declare a companion object inside a class, its properties and functions are shared by all instances of the regular class. It is perfect when we want a bunch of regular classes to share one set of related data. We will see a companion object in action in the next app, and also in the Age database app in the penultimate chapter.
