async function preloadCode(pathname) {
	if (!BROWSER) {
		throw new Error('Cannot call preloadCode(...) on the server');
	}

	const url = new URL(pathname, current.url);

	if (DEV) {
		if (!pathname.startsWith('/')) {
			throw new Error(
				'argument passed to preloadCode must be a pathname (i.e. "/about" rather than "http://example.com/about"'
			);
		}

		if (!pathname.startsWith(base)) {
			throw new Error(
				`pathname passed to preloadCode must start with \`paths.base\` (i.e. "${base}${pathname}" rather than "${pathname}")`
			);
		}

		if (__SVELTEKIT_CLIENT_ROUTING__) {
			const rerouted = await get_rerouted_url(url);
			if (!rerouted || !routes.find((route) => route.exec(get_url_path(rerouted)))) {
				throw new Error(`'${pathname}' did not match any routes`);
			}
		}
	}

	return _preload_code(url);
}
Programmatically imports the code for routes that haven't yet been fetched.
Typically, you might call this to speed up subsequent navigation.

You can specify routes by any matching pathname such as `/about` (to match `src/routes/about/+page.svelte`) or `/blog/*` (to match `src/routes/blog/[slug]/+page.svelte`).

Unlike `preloadData`, this won't call `load` functions.
Returns a Promise that resolves when the modules have been imported.

@param {string} pathname
@returns {Promise<void>}