fix: correctly restore trailing slash in url pathname for data requests

.changeset/mighty-crews-switch.md

@@ -0,0 +1,5 @@
+---
+'@sveltejs/kit': patch
+---
+
+fix: correctly restore trailing slash in url pathname for data requests

.changeset/pink-sloths-join.md

@@ -0,0 +1,5 @@
+---
+'@sveltejs/kit': patch
+---
+
+fix: load trailing slash option from server even when there's no load function

packages/kit/src/core/postbuild/analyse.js

@@ -60,7 +60,7 @@ async function analyse({ manifest_path, env }) {
 		const node = await loader();
 
 		metadata.nodes[node.index] = {
-			has_server_load: node.server?.load !== undefined
+			has_server_load: node.server?.load !== undefined || node.server?.trailingSlash !== undefined
 		};
 	}
 

packages/kit/src/runtime/client/client.js

@@ -31,7 +31,7 @@ import { compact } from '../../utils/array.js';
 import { validate_page_exports } from '../../utils/exports.js';
 import { unwrap_promises } from '../../utils/promises.js';
 import { HttpError, Redirect } from '../control.js';
-import { INVALIDATED_PARAM, validate_depends } from '../shared.js';
+import { INVALIDATED_PARAM, TRAILING_SLASH_PARAM, validate_depends } from '../shared.js';
 import { INDEX_KEY, PRELOAD_PRIORITIES, SCROLL_KEY, SNAPSHOT_KEY } from './constants.js';
 import { stores } from './singletons.js';
 
@@ -1819,6 +1819,9 @@ export function create_client(app, target) {
 async function load_data(url, invalid) {
 	const data_url = new URL(url);
 	data_url.pathname = add_data_suffix(url.pathname);
+	if (url.pathname.endsWith('/')) {
+		data_url.searchParams.append(TRAILING_SLASH_PARAM, '1');
+	}
 	if (DEV && url.searchParams.has(INVALIDATED_PARAM)) {
 		throw new Error(`Cannot used reserved query parameter "${INVALIDATED_PARAM}"`);
 	}

packages/kit/src/runtime/server/respond.js

@@ -29,7 +29,7 @@ import {
 import { get_option } from '../../utils/options.js';
 import { error, json, text } from '../../exports/index.js';
 import { action_json_redirect, is_action_json_request } from './page/actions.js';
-import { INVALIDATED_PARAM } from '../shared.js';
+import { INVALIDATED_PARAM, TRAILING_SLASH_PARAM } from '../shared.js';
 
 /* global __SVELTEKIT_ADAPTER_NAME__ */
 
@@ -100,7 +100,10 @@ export async function respond(request, options, manifest, state) {
 	let invalidated_data_nodes;
 	if (is_data_request) {
 		decoded = strip_data_suffix(decoded) || '/';
-		url.pathname = strip_data_suffix(url.pathname) || '/';
+		url.pathname =
+			strip_data_suffix(url.pathname) +
+				(url.searchParams.get(TRAILING_SLASH_PARAM) === '1' ? '/' : '') || '/';
+		url.searchParams.delete(TRAILING_SLASH_PARAM);
 		invalidated_data_nodes = url.searchParams
 			.get(INVALIDATED_PARAM)
 			?.split('')

packages/kit/src/runtime/shared.js

@@ -12,3 +12,5 @@ export function validate_depends(route_id, dep) {
 }
 
 export const INVALIDATED_PARAM = 'x-sveltekit-invalidated';
+
+export const TRAILING_SLASH_PARAM = 'x-sveltekit-trailing-slash';

packages/kit/test/apps/basics/src/routes/routing/trailing-slash-server/+layout.svelte

@@ -3,8 +3,11 @@
 
 	export let data;
 </script>
+
 <ul>
 	<li><a href="/routing/trailing-slash-server/always">/always</a></li>
+	<li><a href="/routing/trailing-slash-server/ignore">/ignore</a></li>
+	<li><a href="/routing/trailing-slash-server/ignore/">/ignore/</a></li>
 	<li><a href="/routing/trailing-slash-server/never/">/never/</a></li>
 </ul>
 

packages/kit/test/apps/basics/src/routes/routing/trailing-slash-server/ignore/+page.server.js

@@ -0,0 +1 @@
+export const trailingSlash = 'ignore';

packages/kit/test/apps/basics/test/cross-platform/test.js

@@ -936,6 +936,34 @@ test.describe('Routing', () => {
 		);
 	});
 
+	test('trailing slash server with config ignore and no trailing slash in URL', async ({
+		page,
+		clicknav
+	}) => {
+		await page.goto('/routing/trailing-slash-server');
+		await clicknav('[href="/routing/trailing-slash-server/ignore"]');
+		expect(await page.textContent('[data-test-id="pathname-store"]')).toBe(
+			'/routing/trailing-slash-server/ignore'
+		);
+		expect(await page.textContent('[data-test-id="pathname-data"]')).toBe(
+			'/routing/trailing-slash-server/ignore'
+		);
+	});
+
+	test('trailing slash server with config ignore and trailing slash in URL', async ({
+		page,
+		clicknav
+	}) => {
+		await page.goto('/routing/trailing-slash-server');
+		await clicknav('[href="/routing/trailing-slash-server/ignore/"]');
+		expect(await page.textContent('[data-test-id="pathname-store"]')).toBe(
+			'/routing/trailing-slash-server/ignore/'
+		);
+		expect(await page.textContent('[data-test-id="pathname-data"]')).toBe(
+			'/routing/trailing-slash-server/ignore/'
+		);
+	});
+
 	test('trailing slash server with config never', async ({ page, clicknav }) => {
 		await page.goto('/routing/trailing-slash-server');
 		await clicknav('[href="/routing/trailing-slash-server/never/"]');