chore: separate tutorial URLs into svelte and kit

- gives us more leeway with duplicated slugs if needed later on
- makes URL a bit more organized
- will make it easier to set dedicated headers for the SvelteKit tutorial (#301)
- fixes a bug with redirects not being picked up due to prerendering not coming across old slugs

Author: dummdidumm

apps/svelte.dev/src/routes/content.json/+server.ts

@@ -2,6 +2,7 @@ import { index, docs as _docs } from '$lib/server/content';
 import { json } from '@sveltejs/kit';
 import { markedTransform, normalizeSlugify, removeMarkdown } from '@sveltejs/site-kit/markdown';
 import type { Block } from '@sveltejs/site-kit/search';
+import { get_slug } from '../tutorial/[...slug]/content.server';
 
 export const prerender = true;
 
@@ -17,13 +18,12 @@ function get_href(parts: string[]) {
 
 async function content() {
 	const blocks: Block[] = [];
-	const breadcrumbs: string[] = [];
 	const docs = Object.values(_docs.pages).concat(
-		index.tutorial.children.flatMap((topic) =>
-			topic.children.flatMap((section) =>
-				section.children.map((entry) => ({
-					...entry,
-					slug: `tutorial/${entry.slug.split('/').pop()}`
+		index.tutorial.children.flatMap((part) =>
+			part.children.flatMap((chapter) =>
+				chapter.children.map((exercise) => ({
+					...exercise,
+					slug: get_slug(part, exercise)
 				}))
 			)
 		)

apps/svelte.dev/src/routes/tutorial/+page.js

@@ -0,0 +1,46 @@
+import { redirect } from '@sveltejs/kit';
+import { load_exercise, parts } from './content.server';
+
+export const prerender = true;
+
+const redirects = new Map([
+	['reactive-assignments', 'svelte/state'],
+	['reactive-declarations', 'svelte/derived-state'],
+	['reactive-statements', 'svelte/effects'],
+	['updating-arrays-and-objects', 'svelte/deep-state'],
+	['event-modifiers', 'svelte/capturing'],
+	['dom-event-forwarding', 'svelte/spreading-events']
+]);
+
+export async function load({ params }) {
+	if (!params.slug || params.slug === 'svelte') redirect(307, '/tutorial/svelte/welcome-to-svelte');
+	if (params.slug === 'kit') redirect(307, '/tutorial/introducing-sveltekit');
+
+	const r = redirects.get(params.slug);
+	if (r) redirect(307, r);
+	if (!params.slug.includes('/')) redirect(307, `/tutorial/svelte/${params.slug}`);
+
+	return {
+		exercise: await load_exercise(params.slug)
+	};
+}
+
+export function entries() {
+	// These are not findable by the router, but we need to know about them for redirects
+
+	// Old tutorial/... to new tutorial/svelte/...
+	const entries = parts
+		.filter((part) => !part.slug.includes('sveltekit'))
+		.flatMap((part) => part.chapters)
+		.flatMap((chapter) => {
+			return chapter.exercises.map((exercise) => {
+				const slug = exercise.slug.split('/').pop()!;
+				return { slug: redirects.get(slug) || slug };
+			});
+		});
+
+	// So that redirects from these URLs to /tutorial/<svelte/kit>/... work
+	entries.push({ slug: 'svelte' }, { slug: 'kit' });
+
+	return entries;
+}

apps/svelte.dev/src/routes/tutorial/[slug]/+layout.server.ts renamed to apps/svelte.dev/src/routes/tutorial/[...slug]/+layout.server.ts

@@ -33,6 +33,11 @@ let prev: null | { slug: string; title: string } = null;
 
 let files: Record<string, string> = {};
 
+export function get_slug(part: Document, exercise: Document) {
+	const topic = part.slug.split('/').pop()!.includes('sveltekit') ? 'kit' : 'svelte';
+	return `tutorial/${topic}/${exercise.slug.split('/').pop()}`;
+}
+
 export const parts: PartStub[] = index.tutorial.children.map((part) => {
 	return {
 		slug: part.slug,
@@ -42,7 +47,7 @@ export const parts: PartStub[] = index.tutorial.children.map((part) => {
 				slug: chapter.slug.split('/').pop()!,
 				title: chapter.metadata.title,
 				exercises: chapter.children.map((exercise) => {
-					const slug = exercise.slug.split('/').pop()!;
+					const slug = get_slug(part, exercise).slice('tutorial/'.length);
 
 					const stub: ExerciseStub = {
 						slug,
@@ -200,6 +205,7 @@ const default_renderer: Partial<Renderer> = {
 
 export async function load_exercise(slug: string): Promise<Exercise> {
 	if (!(slug in lookup)) {
+		console.log(slug, Object.keys(lookup));
 		error(404, 'No such tutorial found');
 	}