Old page receives new page's props before swapping

[mattwigham]

Version:

• @inertiajs/svelte version: 2.0.0 and 1.3.0
• svelte version: 5.16.0

Describe the problem:

When navigating from one page to another, the old page component is briefly updated with the new page's props before the new page component is swapped in. This causes undefined errors since the old page doesn't have its expected props any longer.

I'm not sure if this is expected behavior, or if it's specific to Svelte 5. This happens when using $props() and $page.props.

Steps to reproduce:

Create two pages link to each other and each receives unique props.

// One.svelte

<script>
  import { Link } from "@inertiajs/svelte";
  let { propOne } = $props(); // set to "prop-one-value" on the server
  $inspect("One", propOne);
</script>

<Link href="/two">Two</Link>

// Two.svelte

<script>
  import { Link } from "@inertiajs/svelte";
  let { propTwo } = $props(); // set to "prop-two-value" on the server
  $inspect("Two", propTwo);
</script>

<Link href="/one">One</Link>

In the browser, navigate using the links and you'll see the following in the console.

init One prop-one-value
update One undefined
init Two prop-two-value
update Two undefined
init One prop-one-value
...