Looks like mixins:<p><a href="https://en.wikipedia.org/wiki/Mixin" rel="nofollow">https://en.wikipedia.org/wiki/Mixin</a>
This "concatenative inheritance" seems like a symptom of JavaScript's limited support for prototypal OO. Objects in Self support multiple prototype slots: you can add to an object without copying more stuff into it.
> Believe it or not, it is the most commonly used form of inheritance in JavaScript.<p>Are extend, assign etc really more common than just working with prototypes? I've personally never used it but written a lot of OO code using prototype delegation.
That's a pretty grandiose term for a pretty straightforward pattern in JS. Other people just call it "mixins" but I guess there is some elaborate academic argument for why that's an entirely different concept even if the two are indistinguishable to the layperson.