Thanks here is complate details and the steps to sovle it:

The error occurs because have to moved vitePreprocess from '@sveltejs/kit/vite to @sveltejs/vite-plugin-svelte

You need to update the import statement in this case:

import { vitePreprocess } from '@sveltejs/vite-plugin-svelte'

also check you have installed the packages:

npm install --save-dev @sveltejs/vite-plugin-svelte

• Read the question and happy you found solution.