[wmf]

It's not about Javascript vs. WASM; it's the DOM. DOMless apps like Figma are much faster.

[esprehn]

The slowness in a React app is not the DOM. Typical apps spend most of their time running component code long before any DOM mutations are committed.

If you look at DOM benchmarks it's extremely fast. Slow web pages come from slow layers on top.

[leptons]

It depends on the app. If the app has many hundreds or even thousands of DOM elements, there's no way to make that work smoothly with React or any other library or framework. Then a canvas based solution can fix things. I know, I've had to fix slow React apps.