Great work, just looking in to Svelte now after reviewing your latest release and video. First thing I looked for was routing, and I see Sapper is essentially batteries-included solution to using Svelte.
Will these always be separate libraries?
Is Sapper basically the create-svelte-app for your framework?
What's the roadmap for Sapper and integrating Svelte v3 changes?
Bringing Sapper up to date is the next big task. In some ways yes, it's a bit like create-svelte-app, though a closer reference point if you're versed in the React world would be Next.js.
We've also mulled creating a React Router equivalent, for people who prefer components-as-routes to files-as-routes.
The gist of Immer is that your framework needs immutable structures, but you want to interact with them imperatively.
It's very interesting, and a reversal of the traditional "functional core, imperative shell" architecture.
https://github.com/immerjs/immer