Improved logic to check whether more older posts are available

src/routes/+page.svelte

@@ -13,13 +13,22 @@ let interval: NodeJS.Timer | null = null;
 let moreOlderPostsAvailable = true;
 let loadingOlderPosts = false;
 
-async function fetchPosts(filter: { since?: string, before?: string }): Promise<Post[]> {
+interface FetchOptions {
+  since?: string,
+  before?: string,
+  count?: number
+}
+
+async function fetchPosts(options: FetchOptions): Promise<Post[]> {
   const params = new URLSearchParams();
-  if (filter?.since !== undefined) {
-    params.set('since', filter.since);
+  if (options?.since !== undefined) {
+    params.set('since', options.since);
   }
-  if (filter?.before !== undefined) {
-    params.set('before', filter.before);
+  if (options?.before !== undefined) {
+    params.set('before', options.before);
+  }
+  if (options?.count !== undefined) {
+    params.set('count', options.count.toFixed(0));
   }
 
   const response = await fetch(`/api/posts?${params}`);
@@ -33,7 +42,7 @@ function filterDuplicates(posts: Post[]): Post[] {
 }
 
 function refresh() {
-  let filter = {};
+  let filter: FetchOptions = {};
   if (data.posts.length > 0) {
     filter = { since: data.posts[0].created_at };
   }
@@ -72,9 +81,9 @@ onMount(async () => {
 
 function loadOlderPosts() {
   loadingOlderPosts = true;
-  let filter = {};
+  const filter: FetchOptions = { count: 20 };
   if (data.posts.length > 0) {
-    filter = { before: data.posts[data.posts.length - 1].created_at };
+    filter.before = data.posts[data.posts.length - 1].created_at;
   }
 
 
@@ -83,7 +92,8 @@ function loadOlderPosts() {
       // Append old posts, filter dupes
       // There shouldn't be any duplicates, but better be safe than sorry
       data.posts = filterDuplicates(data.posts.concat(resp));
-      moreOlderPostsAvailable = true;
+      // If we got less than we expected, there are no older posts available
+      moreOlderPostsAvailable = resp.length < (filter.count ?? 20);
     } else {
       moreOlderPostsAvailable = false;
     }