Virtual dom is an implementation decision for performance a developer shouldn't ...

Waterluvian · on May 19, 2019

You should at least be aware of the gist, lest you obsess over premature optimization.

1. Changes to the DOM cost a ton more than executing JS code.

2. So don't feel too bad when a render() gets called that doesn't change anything because the virtual DOM swallows that.

spankalee · on May 19, 2019

> 1. Changes to the DOM cost a ton more than executing JS code.

The point of the article, and of the performance problems that people actually have with React is that this might be true for a small number of JS operations, but that

1) Tree diffs are computationally complex operations that add up for real-sized apps 2) The diff is actually unnecessary if you simply take into account the structure of templates, so diffs are pure overhead.

So _do_ feel bad when you have a no-op render() in React at least, because the resulting VDOM diff just chewed up CPU and battery for no reason.