As a recent adopter of Svelte, these changes are intriguing but I don't really have a grasp of how I feel about it quite yet.

One thing that I am definitely happy to see is the removal of $: as it should help Typescript users. Personally, I was quite sick of writing:

  let input = 'Hello';
  // ...
  let loudInput: string;
  $: loudInput = `${input)!`;

Instead of:

  let input = 'Hello';
  // ...
  $: loudInput: string = `${input)!`;

It's an incredibly minor thing, but when you do it 1000 times it becomes very frustrating. Having reactivity be rune-based should help TS avoid the syntactic confusion, bringing us to:

  let input = $state('hello');
  // ...
  let loudInput: string = `${input)!`;