Sveltekit: "Error: Request. Query Has Been Replaced by Request. Url. searchParams"

I ran into the same problem. In src/hooks.js replace

const method = request.query.get('_method');

with

const method = request.method;

If you are using npm init svelte@next my-app and using the demo app, you are also going to run into a problem in Header.svelte.

replace

<li class:active={$page.path === '/'}><a sveltekit:prefetch href="/">Home</a></li>
<li class:active={$page.path === '/about'}><a sveltekit:prefetch href="/about">About</a></li>
<li class:active={$page.path === '/todos'}><a sveltekit:prefetch href="/todos">Todos</a></li>

with

<ul>
  <li class:active={$page.url.pathname === '/'}><a sveltekit:prefetch href="/">Home</a></li>
  <li class:active={$page.url.pathname === '/about'}>
   <a sveltekit:prefetch href="/about">About</a>
  </li>
  <li class:active={$page.url.pathname === '/todos'}>
    <a sveltekit:prefetch href="/todos">Todos</a>
  </li>
</ul>

In my case (SvelteKit next 160) it was different than in @klequis answer. The src/hooks.js contained this block of code

The solution to this is actually removing this if block altogether.

I removed it and I confirmed that this assignment is not needed anymore by logging the output console.log(request.method) output: GET

Untested code.

// TODO 
const searchParams = new URL(event.request.url).searchParams;
if (searchParams.has('_method')) {
    event.request = new Request({ ...event.request, method: searchParams.get('_method').toUpperCase()||''}) ;
}