Extend subclasses, mixin composes into a new class (like traits), override and plugin augment existing classes, with override replacing existing methods (which

Extend subclasses, mixin composes into a new class (like traits), override and plugin augment existing classes, with override replacing existing methods (which can break with every new release), and plugin fitting into a hook that remains compatible across releases. All makes perfect sense to me. They’re standard OO techniques, the novelty was introducing them to JS developers.