@wentools/simmer-svelte

Svelte 5 adapters for @wentools/simmer.

Install

# JSR
deno add jsr:@wentools/simmer-svelte

# npm
npx jsr add @wentools/simmer-svelte

Usage

createEventualState

Bridges simmer's EventualResult to Svelte 5 reactive state. Returns the current (cached) value immediately, then automatically updates when fresh data arrives.

<script lang="ts">
  import { createEventualState } from '@wentools/simmer-svelte'

  let { data } = $props()

  // data.patronShowcase is EventualResult<ShowcaseData>
  const showcase = createEventualState(() => data.patronShowcase)
</script>

<!-- Renders immediately with cached data -->
<PatronShowcase data={showcase.value} />

{#if showcase.isRefreshing}
  <LoadingSpinner />
{/if}

{#if showcase.error}
  <p>Failed to refresh: {showcase.error.message}</p>
{/if}

How it works

EventualResult<T> contains { current: T, fresh: Promise<T> | null }.

• current is served immediately (from cache or SSR)
• fresh resolves when updated data arrives from the API

createEventualState wraps this in a reactive rune that:

1. Returns current as value immediately
2. Sets isRefreshing: true while fresh is pending
3. Swaps value to the resolved fresh data automatically
4. Handles race conditions when navigation triggers new requests

License

MIT