[mynegation]

Because when your code changes DOM, browser does not know whether you are going to stop at it for now, or do something else, so it has to re-render. In React you explicitly request application of virtual DOM changes to real DOM once you are done.

[blktiger]

In theory they could add some new methods to the DOM api to allow for this, but it would be non-standard and currently none of the browsers have it.

Something like this maybe?

batchDomChanges(); ... dom changes here ... flushDomChanges();

[yblu]

Or use fastdom[1], which batches reads and writes to reduce layout thrashing.

[1]: https://github.com/wilsonpage/fastdom

[zkhalique]

Well I thought that is why there is requestAnimationFrame.

[jonathancreamer]

Great explanation.