add infinite scroll

src/lib/hooks/getPosts.ts

@@ -1,17 +1,21 @@
 import { apiBase } from "@/stores/url";
 import { sesionStore } from "@/stores/usuario";
 import { get } from "svelte/store";
+import type { Post } from '../../types';
+import { PAGE_SIZE } from '../stores/posts';
 
-export async function getPosts() {
+export async function getPosts(page: number = 1): Promise<Post[]> {
+	const token = get(sesionStore)?.accessToken;
 
+	const headers: HeadersInit = {};
+	if (token) headers.Authorization = `Bearer ${token}`;
 
-	const req = await fetch(`${get(apiBase)}/timeline?pageSize=20`,{
-	headers: {
-	Authorization: `Bearer ${get(sesionStore)?.accessToken}`
+	const res = await fetch(
+		`${get(apiBase)}/timeline?page=${page}&pageSize=${PAGE_SIZE}`,
+		{ headers }
+	);
 
-	}
-	});
-	if (req.ok) {
-		return await req.json();
-	}
-}
+	if (!res.ok) throw new Error('Error cargando posts');
+
+	return res.json();
+}

src/lib/hooks/loadMorePosts.ts

@@ -0,0 +1,32 @@
+import { get } from 'svelte/store';
+import { page, loadingPosts, PAGE_SIZE } from '@/stores/posts';
+import { appendPosts } from '@/stores/posts';
+import { getPosts } from './getPosts';
+
+let finished = false;
+
+export async function loadMorePosts() {
+	if (get(loadingPosts) || finished) return;
+
+	loadingPosts.set(true);
+
+	try {
+		const currentPage = get(page);
+		const newPosts = await getPosts(currentPage);
+
+		if (newPosts.length === 0) {
+			finished = true;
+			return;
+		}
+
+		appendPosts(newPosts);
+
+		if (newPosts.length < PAGE_SIZE) {
+			finished = true;
+		} else {
+			page.update(p => p + 1);
+		}
+	} finally {
+		loadingPosts.set(false);
+	}
+}

src/lib/stores/posts.ts

@@ -1,29 +1,42 @@
 import { writable } from 'svelte/store';
 import type { Post } from '../../types';
 
-export const posts = writable<Post[] | undefined>(undefined);
+export const posts = writable<Post[]>([]);
+export const loadingPosts = writable(false);
+export const page = writable(1);
+
+export const PAGE_SIZE = 20;
 
 export const setPosts = (newPosts: Post[]) => {
 	posts.set(newPosts);
 };
 
-export const addPost = (post: Post) => {
-	posts.update((currentPosts) => [post, ...currentPosts]);
+export const appendPosts = (newPosts: Post[]) => {
+	posts.update((current) => [...current, ...newPosts]);
 };
 
-export const updatePostStore = (postId: string, updatedData: Partial<Post>) => {
-	posts.update((currentPosts) =>
-		currentPosts.map((post) => (post.id === postId ? { ...post, ...updatedData } : post))
+export const addPost = (post: Post) => {
+	posts.update((current) => [post, ...current]);
+};
+
+export const updatePostStore = (
+	postId: string,
+	updatedData: Partial<Post>
+) => {
+	posts.update((current) =>
+		current.map((post) =>
+			post.id === postId ? { ...post, ...updatedData } : post
+		)
 	);
 };
 
 export const removePost = (postId: string) => {
-	posts.update((currentPosts) => {
-		const a = currentPosts.filter((post) => post.id !== postId);
-		return a;
-	});
+	posts.update((current) =>
+		current.filter((post) => post.id !== postId)
+	);
 };
 
 export const resetPosts = () => {
-	posts.set(undefined);
+	posts.set([]);
+	page.set(1);
 };

src/routes/+page.svelte

@@ -1,56 +1,71 @@
 <script lang="ts">
-	import { goto, replaceState } from '$app/navigation';
+	import { replaceState } from '$app/navigation';
+	import { page } from '$app/state';
+	import { onMount } from 'svelte';
 	import Card from '@/components/ui/card/card.svelte';
 	import { Content } from '@/components/ui/card';
-	import { sesionStore } from '@/stores/usuario';
-	import CrearPost from '@/components/crear-post.svelte';
-	import { posts, resetPosts, setPosts, updatePostStore } from '@/stores/posts';
-	import PostCard from '@/components/PostCard.svelte';
-	import type { Post } from '../types';
-	import ModalEditar from './[perfil]/modalEditar.svelte';
-	import { updatePost } from '@/hooks/updatePost';
-	import { fade, slide } from 'svelte/transition';
-	import { getPosts } from '@/hooks/getPosts';
 	import Spinner from '@/components/ui/spinner/spinner.svelte';
-	import { page } from '$app/state';
 	import Dialog from '@/components/ui/dialog/dialog.svelte';
 	import DialogContent from '@/components/ui/dialog/dialog-content.svelte';
+	import CrearPost from '@/components/crear-post.svelte';
+	import PostCard from '@/components/PostCard.svelte';
+	import ModalEditar from './[perfil]/modalEditar.svelte';
+	import { sesionStore } from '@/stores/usuario';
+	import {
+		posts,
+		updatePostStore,
+		loadingPosts
+	} from '@/stores/posts';
+	import { updatePost } from '@/hooks/updatePost';
+	import { loadMorePosts } from '@/hooks/loadMorePosts';
+	import type { Post } from '../types';
+	import { fade, slide } from 'svelte/transition';
 
-	$effect(() => {
-		resetPosts();
-		(async () => {
-			setPosts(await getPosts());
-		})();
+	let postAModificar: Post | null = null;
+	let mensajeError = '';
+	let sentinel: HTMLDivElement;
+
+	onMount(() => {
+		loadMorePosts();
+
+		const observer = new IntersectionObserver(
+			([entry]) => {
+				if (entry.isIntersecting) {
+					loadMorePosts();
+				}
+			},
+			{ rootMargin: '200px' }
+		);
+
+		observer.observe(sentinel);
+		return () => observer.disconnect();
 	});
 
-	let postAModificar: Post | null = $state(null);
-	let mensajeError = $state('');
-
 	async function handleEditar(e: SubmitEvent) {
 		e.preventDefault();
-		if (postAModificar == null) return;
+		if (!postAModificar) return;
+
 		await updatePost(
 			postAModificar,
-			(postnuevo: Post) => updatePostStore(postAModificar!.id, postnuevo),
-
+			(postNuevo: Post) =>
+				updatePostStore(postAModificar!.id, postNuevo),
 			mensajeError
 		);
 		postAModificar = null;
 	}
-	let from = $state(page.url.searchParams.get('from'));
-	$effect(() => {
-		goto('/', { replaceState: true });
-	});
+
+	let from = page.url.searchParams.get('from');
+
+	if (from) {
+		replaceState('/', {});
+	}
 </script>
 
-{#if from == 'cambio_contraseña'}
-	<Dialog
-		open={true}
-		onOpenChange={() => {
-			from = '';
-		}}
-	>
-		<DialogContent>Se cambio la contraseña del usuario exitosamente</DialogContent>
+{#if from === 'cambio_contraseña'}
+	<Dialog open>
+		<DialogContent>
+			Se cambió la contraseña del usuario exitosamente
+		</DialogContent>
 	</Dialog>
 {/if}
 
@@ -65,22 +80,25 @@
 <div class="flex min-h-fit w-full items-center justify-center p-6 md:p-10">
 	<div class="w-full max-w-6xl">
 		<div class="flex flex-col gap-2">
-			{#if $sesionStore !== null}
+			{#if $sesionStore}
 				<CrearPost />
 			{/if}
 			<hr />
 
-			{#if $posts === undefined}
+			{#if $posts.length === 0 && $loadingPosts}
 				<Card>
 					<Content class="flex items-center justify-center gap-2">
 						<Spinner class="h-10 w-10" />
 						<p>Cargando</p>
 					</Content>
 				</Card>
-			{:else if $posts.length <= 0}
+
+			{:else if $posts.length === 0}
 				<Card>
 					<Content>
-						<p class=" text-center leading-7 not-first:mt-6">No hay Posts que mostrar</p>
+						<p class="text-center leading-7">
+							No hay Posts que mostrar
+						</p>
 					</Content>
 				</Card>
 			{:else}
@@ -91,10 +109,20 @@
 				{/each}
 			{/if}
 		</div>
+		<div bind:this={sentinel} class="h-1"></div>
+
+		{#if $loadingPosts && $posts.length > 0}
+			<div class="flex justify-center py-4">
+				<Spinner />
+			</div>
+		{/if}
 	</div>
 </div>
 {#if postAModificar}
 	<div in:fade>
-		<ModalEditar callbackfn={handleEditar} bind:post={postAModificar} />
+		<ModalEditar
+			callbackfn={handleEditar}
+			bind:post={postAModificar}
+		/>
 	</div>
-{/if}
+{/if}