I read this long ago and I love Rich Harris and I think he is a super smart guy. But the problem as I see it is that he focuses on VDOM as just a performance hedge. As browsers improve (or rather as the market consolidates on WebKit variants as is happening now), then certain DOM operations that took substantially longer on average on IE or Edge vs. Chrome will no longer be as much of a problem, which is my view of what the VDOM was trying to solve. There are some operations that depending on the browser and how the internal mechanics of the layout engine work will take substantially longer on one browser vs another for instance. You are at the mercy of each layout engine's architecture. In this case, if you use a VDOM to calculate the simplest operation to be performed and just push the end results with the simplest operations manageable, you can elide away the differences between certain DOM operations taking longer than others across browsers. Setting innerHTML for example on IE (Trident), Edge (EdgeHTML), Safari (non-Blink WebKit), Firefox (Gecko) and Chrome/Chromium (Blink) is likely the best way to ensure consistent performance since it is one of the base operations you will need to do to manipulate HTML.
I personally love the idea of the VDOM, because it liberates the content from being stuck to one document type: HyperText. While true when VDOM showed up on the scene, Facebook and others said the VDOM would help cure performance issues and that was the main selling point.. as we see now with things like ReactPixi, and Netflix using React for some of their apps - the VDOM is infinitely valuable for transcending the limits of HyperText and instead abstracting it away so that content may be projected by any sort of renderer using the same scaffolding as web pages. If you code to just the DOM - that is is where you will stay. Forever.
“ If you code to just the DOM - that is is where you will stay. Forever.”
Svelte native exists…
The VDOM which mirrors the document DOM is an implementation detail of React, as something sitting between the actual DOM, and the VDOM fragment returned by a React view. It’s true that if the document DOM gets fast enough, the mirroring VDOM could go away, but some diffing algorithm would still have to reconcile the document DOM with whatever fragment is returned from a view.
I think one of the realisations of Svelte is that rather than returning arbitrary runtime generated DOM fragments from views, it is better to have the view implemented by a template that a compiler can understand and manipulate at compile-time. Here we trade off some expressivity (run-time generated DOM) for the ability to do much much more at compile time - I think this is the real point that should be being made in the article.
I personally love the idea of the VDOM, because it liberates the content from being stuck to one document type: HyperText. While true when VDOM showed up on the scene, Facebook and others said the VDOM would help cure performance issues and that was the main selling point.. as we see now with things like ReactPixi, and Netflix using React for some of their apps - the VDOM is infinitely valuable for transcending the limits of HyperText and instead abstracting it away so that content may be projected by any sort of renderer using the same scaffolding as web pages. If you code to just the DOM - that is is where you will stay. Forever.