"Unlike method invocation, inheritance violates encapsulation" Item 16 of Effective Java 2nd Edition. To the original article, I would improve the wording so that it is clear whether the author is against class hierarchies in Javascript or classes in Javascript. It is not clear to me.

One practical example: In Javascript (CoffeeScript), null values can propagate for a very long time. Calling a non-existent method throws an error immediately, while using a nonexistent field (because it changed in the super class) is not that easy to track down. From my CoffeeScript experience, almost any inheritance brought us a headache when we rapidly iterated on our code - but that doesn't mean that CS class construct isn't useful in defining recipes for well-encapsulated objects.