A few years ago nobody criticized an author for calling his work a book if it didn't have an electronic version. We are now clearly in a transition phase [1], but it is plain that soon it will be acceptable and in fact expected to forgo the print edition when publishing "a book". A significant threat to content preservation, but that's another story.
What distinguishes a book is the 'form factor'. Obviously we are talking about an e-book. Nonetheless little care has been put into producing a 'book': not TOC, no index, no page numbers, etc.
(Obviously this is all independent of the content.)
These are outdated requests, maybe with the exception of the TOC, which soon should also be taken care of by technology [1].
Regarding the index, if you are willing to visit the single-page version, a simple CTRL-F gives you the 70 references to "DOM", for instance. Your modern browser quickly shows how those references are spread in the document. That is pretty much an optimal index to me, with an unlimited number of entries, rendering the separate and physically constrained notion of index obsolete.
And why pages? In today's world of wildly diverse screen sizes and resolutions, please let the content flow. I remember being led to the wrong place of a book in my college years just because the edition I consulted happened to different from the author's, but I found that reasonable in the paper age. Semantically demarcated concepts such as chapters or sections have always been referred in this way, and rightly so. If you think about it, page numbers only helped you locate verbatim excerpts such as "to be, or not to be" in [2]. A completely valid and efficient artifact of the pre-digital era, which has now become dispensable, just as indexes have.
I can live with that if I generate a PDF from web content, but I'd expect a book to have a better print version and a better quality PDF version...