I want to add some extra methods closely related to Book without extending Book. So I found the decorator pattern.Most examples I have seen are eg. extending an abstract decorator class which implements an interface etc.I am wondering if this could be considered as decorator pattern?class Book { ... }class MyBookDecorator {  constructor ( Book book ) {    this->book = book  }  extraMethod() {    ...  }}myBook = new MyBookDecorator( book );myBook->extraMethod();If not, is this a valid pattern to use?Thank you in advance!
Could this be called a decorator pattern?
design patterns;object oriented;patterns and practices