This is the first I'm hearing of incremental-dom. Can anyone explain what it is? According to their readme:

> It differs from the established virtual DOM approach in that no intermediate tree is created (the existing tree is mutated in-place).

Direct DOM manipulation is something the DOM itself has had an API for since about 1995 (and there are plenty of nice wrappers for it). What value does this provide on top of that? Does it batch up changes for requestAnimationFrame()?

With incremental-dom, you're still re-running code to "generate" an entire DOM tree on every state change, so you have the React-like convenience and correctness of not writing individual mutations. But it doesn't create an intermediate represention like React. Instead, incremental-dom patches the real DOM as soon as your code calls into the elementOpen/elementClose/etc functions. Thus, significantly reduced memory allocations and GC thrashing.

I poked around on vdom benchmark[1], and I got the following times:

  incremental-dom 0.1.0	  276343
  React 0.13.1	          586353
  mithril 0.2.0	          602722
  virtual-dom 2.0.1        99136

Is that argument correct? Is reading the DOM actually not so problematic, as long as the modification you make to it are minimal (which seems to be the strategy here)?

One conceivable advantage of this approach seems to be that you can use the native event system directly, but I can't find any mention of event handling in the documentation. I'm wondering if a kind of flux-type architecture would work here, but using jquery, say, to subscribe to events.

[1] http://vdom-benchmark.github.io/vdom-benchmark/

Virtual DOM approaches never really were about performance. They are about being able to write idempotent render functions in declarative style so that you don't need to deal with massive amounts of DOM state management.

In the end you want to write a function that just expresses what the state of the DOM should be depending on the input parameters and have something deal with applying those changes to a very stateful API. If the application state changes, all you want to do is say 'things have changed somehow, just re-render this component'.

This was possible before with classic templating, but it wasn't very efficient and had problems when dealing with re-rendering interactive elements. You would lose focus on input fields for example, and had to use some post-render hooks to fix the state of the DOM up afterwards.

Using virtual DOM structures fixed this problem in an elegant way and allowed rendering to the DOM to be integrated into more functional programming styles, which made more reactive architectures possible.

It all boils down to humans not being good with reasoning about state changes over time and how to express those imperatively. The only solution to that is not to do it and go more functional.

This is also why I am not a big fan of things like incremental-dom. It ignores the whole idea why we wanted declarative DOM handling in the first place and replaces it with a very imperative and side-effect heavy API. In that case, just use the DOM directly.

"React abstracts away the DOM from you, giving a simpler programming model and better performance" https://github.com/facebook/react

It seems strange to me that many developers are now trying to convince everyone that vdom wasn't selling as a way to get better performance. Yes, getting rid of data changes over time is important property of vdom approaches, but when all this vdom hype were started, everyone is also talked how awesome it is in terms of performance.