That's funny; I think that's the only part of what the document proposes I like. -- Well, okay, that's not really true; there are a lot of bits that just make sense, either because they hurt performance for little benefit (holes in arrays) or they're just dumb (arguments.caller). But I don't like gratuitously locking things down in a way that makes highly dynamically-typed code harder to write, where it doesn't seem to solve a real unavoidable performance problem: for example, the ban on constructors leaking 'this', and the oddly specific recursion limitations. In general, the document seems to express the sentiment that only statically typed code matters, which I think is short-sighted. I also dislike, among other performance-unrelated changes, the "let's fix C" syntax bits, such as banning fallthrough, which is just likely to annoy programmers familiar with C (who are used to writing code that relies on it on occasion).

However, making nonexistent property accesses silently return undefined is just an amazing way to ensure typos in property names never get caught. I don't think `foo.bar || baz` is much to sacrifice - Python, for example, has getattr(foo, 'bar', baz), which works fine, and has the benefit of returning foo.bar if it exists at all, not just if it's a truthy value.