src/routes/+page.svelte

@@ -13,22 +13,35 @@ let interval: NodeJS.Timer | null = null;
 let moreOlderPostsAvailable = true;
 let loadingOlderPosts = false;
 
-function refresh() {
+async function fetchPosts(filter: { since?: string, before?: string }): Promise<Post[]> {
   const params = new URLSearchParams();
-  if (data.posts.length > 0) {
-    params.set('since', data.posts[0].created_at);
+  if (filter?.since !== undefined) {
+    params.set('since', filter.since);
   }
-  fetch(`/api/posts?${params}`)
-  .then(r => r.json())
-  .then((resp: Post[]) => {
+  if (filter?.before !== undefined) {
+    params.set('before', filter.before);
+  }
+
+  const response = await fetch(`/api/posts?${params}`);
+  return await response.json();
+}
+
+function filterDuplicates(posts: Post[]): Post[] {
+  return posts.filter((obj, index, arr) => {
+    return arr.map(mapObj => mapObj.url).indexOf(obj.url) === index;
+  });
+}
+
+function refresh() {
+  let filter = {};
+  if (data.posts.length > 0) {
+    filter = { since: data.posts[0].created_at };
+  }
+  fetchPosts(filter).then(resp => {
     if (resp.length > 0) {
       // Prepend new posts, filter dupes
       // There shouldn't be any duplicates, but better be safe than sorry
-      const combined = resp.concat(data.posts);
-      const filteredPosts = combined.filter((obj, index, arr) => {
-        return arr.map(mapObj => mapObj.url).indexOf(obj.url) === index;
-      });
-      data.posts = filteredPosts;
+      data.posts = filterDuplicates(resp.concat(data.posts));
     }
   })
   .catch(e => {
@@ -57,23 +70,19 @@ onMount(async () => {
   }
 });
 
-async function loadOlderPosts() {
+function loadOlderPosts() {
   loadingOlderPosts = true;
-  const params = new URLSearchParams();
+  let filter = {};
   if (data.posts.length > 0) {
-    params.set('before', data.posts[data.posts.length - 1].created_at);
+    filter = { before: data.posts[data.posts.length - 1].created_at };
   }
-  await fetch(`/api/posts?${params}`)
-  .then(r => r.json())
-  .then((resp: Post[]) => {
+
+
+  fetchPosts(filter).then(resp => {
     if (resp.length > 0) {
       // Append old posts, filter dupes
       // There shouldn't be any duplicates, but better be safe than sorry
-      const combined = data.posts.concat(resp);
-      const filteredPosts = combined.filter((obj, index, arr) => {
-        return arr.map(mapObj => mapObj.url).indexOf(obj.url) === index;
-      });
-      data.posts = filteredPosts;
+      data.posts = filterDuplicates(data.posts.concat(resp));
       moreOlderPostsAvailable = true;
     } else {
       moreOlderPostsAvailable = false;