D'après ce que j'ai compris, les framework framework VueJS et ReactJS utilisent des runtime. Ce n'est pas le cas de Svelte qui est un framework qui nécessite une phase de compilation, il n'utilise pas de runtime.

C'est une différence majeure entre les frameworks VueJS et ReactJS versus Svelte.

Je dis cela avec des pincettes, mais il me semble que cela permet à Svelte d'implémenter des solutions "élégantes" non possibles avec runtime. À vérifier…

Aller plus loin sur ce sujet :

• Extrait de Svelte 3: Rethinking reactivity :

  Svelte is a component framework — like React or Vue — but with an important difference. Traditional frameworks allow you to write declarative state-driven code, but there's a penalty: the browser must do extra work to convert those declarative structures into DOM operations, using techniques like virtual DOM diffing that eat into your frame budget and tax the garbage collector.

  Instead, Svelte runs at build time, converting your components into highly efficient imperative code that surgically updates the DOM. As a result, you're able to write ambitious applications with excellent performance characteristics.

• Frameworks without the framework: why didn't we think of this sooner? You can't write serious applications in vanilla JavaScript without hitting a complexity wall. But a compiler can do it for you.

• Virtual DOM is pure overhead