I believe there is no official plugin for Svelte. So it may not be as good as the support for React/Angular/Vue. But once Svelte is a bit more popular, I think JetBrains will release a plugin.

Not bad. I’ve been using the Svelte plugin by Tomasz Błachut. But I don’t think the plugin supports TypeScript yet.

Easier, due to the language-server Svelte uses to support TypeScript. It should be relatively trivial for somebody to implement now.