Transition between loading states in the album Ui

frontend/src/routes/Home.tsx

@@ -1,49 +1,90 @@
-import { For, Show, createEffect, createMemo, createResource, createSignal, onCleanup, onMount } from "solid-js";
-import { GetAlbumCover, GetRandomAlbums, LoadRandomAlbums } from "../../wailsjs/go/main/App";
+import { batch, createEffect, createMemo, createResource, createSignal, onMount } from "solid-js";
+import { GetAlbumCover, GetRandomAlbums, TriggerAlbumReload } from "../../wailsjs/go/main/App";
 import { main } from "../../wailsjs/go/models";
+import { createStore } from "solid-js/store";
+
+type AlbumsData = {
+    status: "loading" | "ok",
+    albums: Array<main.Album | null>
+}
 
 export function Home() {
     const [hidden, setHidden] = createSignal(true);
-    const [albums, {mutate, refetch}] = createResource<Array<main.Album | null>>(GetRandomAlbums);
+
+    const [albumsStore, setAlbumsStore] = createStore<AlbumsData>({
+        status: "loading",
+        albums: new Array(20).fill(null),
+    });
 
     onMount(() => {
         // Fade in the UI
         setTimeout(() => setHidden(false), 150);
+        // Load the albums
+        loadAlbums();
     });
 
-    const reload = () => {
-        LoadRandomAlbums();
-        mutate((new Array(20)).map(() => null));
-        setTimeout(refetch, 100);
+    // Loads the random albums from Go.
+    // This function, when called multiple times, returns the same set.
+    const loadAlbums = async() => {
+        const response = await GetRandomAlbums();
+
+        // Update the albums
+        batch(() => {
+            for (let i = 0; i < response.length; i += 1) {
+                const album = response[i];
+
+                setAlbumsStore("albums", i, album);
+            }
+        });
     };
 
+    const triggerAlbumReload = () => {
+        // Assign all albums to null
+        batch(() => {
+            for (let i = 0; i < 20; i += 1) {
+                setAlbumsStore("albums", i, null);
+            }
+        });
+
+        TriggerAlbumReload();
+        setTimeout(loadAlbums, 50);
+    };
+
+    const els = albumsStore.albums.map((_, idx) => (<Album albums={albumsStore.albums} idx={idx} />));
+
     return (
         <div class={`min-h-screen ${hidden() ? "opacity-0" : "opacity-100"} transition-opacity`}>
             <h1 class="font-black text-2xl pt-6 pb-4 pl-2">
                 Random albums
                 <button
                     class="text-xs font-normal mx-1 p-1 rounded underline hover:bg-zinc-900"
-                    onClick={reload}
+                    onClick={triggerAlbumReload}
                 >
                     Reload
                 </button>
             </h1>
             <div class="pb-4 overflow-scroll whitespace-nowrap">
-                <For each={albums()}>
-                    {(album) => <Album album={album} />}
-                </For>
+                {els}
             </div>
         </div>
     );
 }
 
-function Album(props: { album: main.Album | null }) {
-    const [coverBytes, {mutate, refetch}] = createResource<Array<number> | null>(async() => GetAlbumCover(props.album?.id ?? ""));
+function Album(props: { albums: Array<main.Album | null>, idx: number }) {
+    const [coverBytes, {mutate, refetch}] = createResource<Array<number> | null>(async() => GetAlbumCover(props.albums[props.idx]?.id ?? ""));
+    const [albumName, setAlbumName] = createSignal("");
+    const [artistName, setArtistName] = createSignal("");
+
+    const album = createMemo(() => props.albums[props.idx]);
 
     createEffect(() => {
-        if (!props.album) {
+        const a = album();
+        if (a === null) {
             mutate(null);
             return;
+        } else {
+            setAlbumName(a.name);
+            setArtistName(a.albumArtist);
         }
 
         refetch();
@@ -57,27 +98,24 @@ function Album(props: { album: main.Album | null }) {
         return `data:;base64,${bytes}`;
     });
 
-    const isNull = createMemo(() => !props.album);
+    const isNull = createMemo(() => !album());
     const opacity = createMemo(() => `${isNull() ? "opacity-0" : "opacity-100"} transition-opacity`);
 
     return (
         <div class="inline-block mx-2 p-1 w-32 rounded bg-zinc-900">
-            <Show when={isNull()}>
-                <div class="w-30 h-30" />
-            </Show>
-            <Show when={!isNull()}>
+            <div class="w-30 h-30" >
                 <img
                     class={`inline-block rounded w-30 h-30 transition-opacity ${coverBytes.state === "ready" ? "opacity-100" : "opacity-0"}`}
                     src={base64Image()}
                     alt=""
                 />
-            </Show>
+            </div>
 
             <div class={`text-sm overflow-hidden overflow-ellipsis pt-1 ${opacity()}`}>
-                {props.album?.name ?? "..."}
+                {albumName()}
             </div>
             <div class={`text-xs overflow-hidden overflow-ellipsis ${opacity()}`}>
-                {props.album?.albumArtist ?? "..."}
+                {artistName()}
             </div>
 
         </div>

frontend/wailsjs/go/main/App.d.ts

@@ -8,6 +8,6 @@ export function GetRandomAlbums():Promise<Array<main.Album>>;
 
 export function Greet(arg1:string):Promise<string>;
 
-export function LoadRandomAlbums():Promise<void>;
-
 export function Login(arg1:string,arg2:string,arg3:string):Promise<boolean>;
+
+export function TriggerAlbumReload():Promise<void>;

frontend/wailsjs/go/main/App.js

@@ -14,10 +14,10 @@ export function Greet(arg1) {
   return window['go']['main']['App']['Greet'](arg1);
 }
 
-export function LoadRandomAlbums() {
-  return window['go']['main']['App']['LoadRandomAlbums']();
-}
-
 export function Login(arg1, arg2, arg3) {
   return window['go']['main']['App']['Login'](arg1, arg2, arg3);
 }
+
+export function TriggerAlbumReload() {
+  return window['go']['main']['App']['TriggerAlbumReload']();
+}

session.go

@@ -69,7 +69,7 @@ func (a *App) Login(server, username, password string) (bool, error) {
 }
 
 // Triggers a reload of random albums
-func (a *App) LoadRandomAlbums() {
+func (a *App) TriggerAlbumReload() {
 	go loadAlbums(serverUrl)
 }