In many object-oriented languages, the concept of protected
members allows properties and methods to be accessible within the class they are defined, as well as by subclasses. JavaScript, however, does not natively support protected
members. This article introduces a novel approach to simulate protected
access in JavaScript classes using symbols and private fields.
JavaScript provides private
fields, but they are not accessible to any derived classes. This limitation means that developers cannot use private
fields to directly implement protected
members, which are a staple in many other object-oriented languages.
The solution involves using symbols as keys for protected
properties and methods, ensuring that only the class and its subclasses have access to them. This is achieved by: