[Everlag]

Is the value proposition here the CSS performance benefits of shadow DOM without needing shadow DOM? If so, its surprising there's no direct comparison in the link.

I could actually see this being pretty compelling for easy performance wins. Its much easier to adopt a single CSS property versus a different model for DOM interaction. The churn in the spec and various implementations didn't help shadow DOM adoption at all.

Its 2020 and I've been using shadow DOM(plus web components) for 6 years in side projects. When the stack has native support its great; it runs fast and is a pleasure to develop. The downside is you have to be willing to swallow polyfills that degrade performance when you don't have native support.

If 2020 isn't the year of shadow DOM, maybe 2022 can be the year of shadow DOM polyfills that don't ruin performance.

[randomfool]

Nope.

Shadow DOM isolates selectors, style sheets, etc. It’s about a public/private API for elements.

Contains is about layout and rendering hints to the browser.