{await getSummary()}
``` Do not rely on implicit blocking. See [Remote queries and commands](references/remote-queries-and-commands.md). ### Track reactive reads precisely - Treat reactive reads after an `await` written directly in `$derived(...)` as dependencies. Reads hidden in a called helper are not covered by that rule. - Expect `$effect` to subscribe only to values read synchronously during its latest execution. Reads after `await` or in timers are not tracked. - Read a proxy property, not just the proxy object, when an effect must react to that property's mutations. - Do not expect destructuring from a `$state` proxy to stay reactive. - Do not expect `$derived` results to be deep-proxied. ### Preserve state ownership A fallback object supplied while destructuring `$props()` is an ordinary object, not a state proxy. Mutating parent-owned state can update the parent, but warns unless the prop is explicitly bindable. Design child-to-parent writes as bindings or callbacks instead of silently mutating ownership. Class fields initialized with `$state` compile to non-enumerable accessors. Do not serialize or spread such instances expecting those fields to appear; expose serializable values explicitly. ### Treat prerender conflicts as build errors - A prerendered root `+server.js` must return HTML. - A prerenderable route containing both `+page` and `+server` is ambiguous and fails early; pages otherwise take precedence during prerendering. - Configure `prerender.handleInvalidUrl` for malformed crawl targets. ### Account for navigation ordering During navigation, SvelteKit blurs the active element before updating the component. `blur` and `focusout` handlers therefore see outgoing data. Snapshot restoration happens after `afterNavigate` callbacks. ### Recheck generated and build configuration Generated TypeScript configuration no longer injects `types: ['node']`. Add Node types yourself only when project code needs them. Preserve explicit Vite 8 `codeSplitting`; SvelteKit no longer replaces it unnecessarily. If the root route tree sets `csr = false`, SvelteKit can omit the client build entirely. Do not assume client artifacts exist in a fully server-rendered build. ## Runes and component quick reference ### Coordinate asynchronous UI Use `$effect.pending()` to count promises pending in the current boundary; child boundaries are excluded. Use `$state.eager(value)` for immediate feedback that must not wait for synchronized asynchronous updates. ```svelte {#if $effect.pending()}Saving…
{/if} Home ``` ### Use derived state for optimistic UI A `$derived` binding declared with `let` can be reassigned. Its optimistic value lasts until a dependency changes and the derived expression recalculates. ```svelte ``` Destructuring directly from `$derived(...)` creates individually reactive bindings: ```js let { a, b } = $derived(makeValues()); ``` ### Generate hydration-stable IDs Use `$props.id()` for component-instance IDs shared by server rendering and hydration: ```svelte ``` ### Prefer attachments for element lifecycle behavior Apply an attachment with `{@attach ...}`. It receives the mounted element and may return cleanup logic: ```svelte ``` Adapt an existing action with `fromAction`. For parameterized actions, pass a function that returns the argument. Library-authored spread props can attach behavior with the symbol from `createAttachmentKey()`. ### Respect snippet constraints Snippet parameters support defaults and destructuring, but not rest parameters. Top-level snippets can be exported from `