Query params are not available within load function with adapter-vercel

[wiesson]

Describe the bug

It looks like that with adapter-vercel the query params within the load function are not available:

<script context="module">
  export async function load({page}) {
    console.log({page}) // page.query.URLSearchParams {} is always empty
    return {
      props: {
        query: page.query
      }
    }
  }
</script>

Logs
Vercel function log

[GET] /issues/631?q=pizza
09:45:59:38
{
  page: {
    host: undefined,
    path: '/issues/631',
    query: URLSearchParams {},
    params: {}
  }
}

To Reproduce

git clone [email protected]:wiesson/sveltekit-vercel.git
vc 

I'm assuming vercel-cli is installed and user is logged in

Expected behavior
Query parameters should be available

Information about your SvelteKit Installation:

  System:
    OS: macOS 11.2.3
    CPU: (8) arm64 Apple M1
    Memory: 204.09 MB / 16.00 GB
    Shell: 5.8 - /bin/zsh
  Binaries:
    Node: 15.12.0 - /usr/local/bin/node
    Yarn: 1.22.10 - /usr/local/bin/yarn
    npm: 7.6.3 - /usr/local/bin/npm
  Browsers:
    Chrome: 89.0.4389.90
    Firefox: 87.0
    Safari: 14.0.3
  npmPackages:
    @sveltejs/kit: next => 1.0.0-next.58 
    svelte: ^3.35.0 => 3.35.0 

Severity
The behavior is different to adapter-node

[PatrickG]

Possible duplicate #586

To get the value of a query param, you need to use page.query.get('key').
To get all query params, like in your example, you need to use Object.fromEntries(page.query).

[wiesson]

I know and I did that - for sake of simplicity, I removed all that to make the example smaller - maybe not the best idea 😅 Here is a slightly longer case:

<script context="module">
  import { writable } from "svelte/store";

  export async function load({ page }) {
    const { query } = page;
    const q = query.get("q") || "";
    console.log("load", { page })
    return {
      props: {
        q: writable(q),
        s: q,
        t: "I am a string",
        w: writable("Writable here 👋")
      },
    };
  }
</script>

<script>
  import { onMount } from "svelte";
  import { page } from "$app/stores";
  export let q = writable("");
  export let t = "";
  export let s = "";
  export let w = writable("");

  console.log($page)

  onMount(async () => {
    console.log("---");
    console.log($q);
    console.log(t);
    console.log(s);
    console.log($w);
    console.log("---");
    console.log($page)
  });
</script>

<div>s: {s}</div>
<div>q: {$q}</div>
<div>t: {t}</div>
<div>w: {$w}</div>

Here is a slightly longer example,

I expect an output like this for ?q=pizza:

s: pizza
q: pizza
t: I am a string
w: Writable here 👋

but s and q are empty when using the adapter-vercel

Example: https://sveltekit-vercel.vercel.app/queryparams?q=pizza