feat(web): persist scroll position on navigation back to album

web/src/lib/actions/scroll-memory.ts

@@ -0,0 +1,87 @@
+import { navigating } from '$app/stores';
+import { AppRoute, SessionStorageKey } from '$lib/constants';
+import { handlePromiseError } from '$lib/utils';
+
+interface Options {
+  /**
+   * {@link AppRoute} for subpages that scroll state should be kept while visiting.
+   *
+   * This must be kept the same in all subpages of this route for the scroll memory clearer to work.
+   */
+  routeStartsWith: AppRoute;
+  /**
+   * Function to clear additional data/state before scrolling (ex infinite scroll).
+   */
+  beforeClear?: () => void;
+}
+
+interface PageOptions extends Options {
+  /**
+   * Function to save additional data/state before scrolling (ex infinite scroll).
+   */
+  beforeSave?: () => void;
+  /**
+   * Function to load additional data/state before scrolling (ex infinite scroll).
+   */
+  beforeScroll?: () => Promise<void>;
+}
+
+/**
+ * @param node The scroll slot element, typically from {@link UserPageLayout}
+ */
+export function scrollMemory(
+  node: HTMLElement,
+  { routeStartsWith, beforeSave, beforeClear, beforeScroll }: PageOptions,
+) {
+  const unsubscribeNavigating = navigating.subscribe((navigation) => {
+    const existingScroll = sessionStorage.getItem(SessionStorageKey.SCROLL_POSITION);
+    if (navigation?.to && !existingScroll) {
+      // Save current scroll information when going into a subpage.
+      if (navigation.to.url.pathname.startsWith(routeStartsWith)) {
+        beforeSave?.();
+        sessionStorage.setItem(SessionStorageKey.SCROLL_POSITION, node.scrollTop.toString());
+      } else {
+        beforeClear?.();
+        sessionStorage.removeItem(SessionStorageKey.SCROLL_POSITION);
+      }
+    }
+  });
+
+  handlePromiseError(
+    (async () => {
+      await beforeScroll?.();
+
+      const newScroll = sessionStorage.getItem(SessionStorageKey.SCROLL_POSITION);
+      if (newScroll) {
+        node.scroll({
+          top: Number.parseFloat(newScroll),
+          behavior: 'instant',
+        });
+      }
+      beforeClear?.();
+      sessionStorage.removeItem(SessionStorageKey.SCROLL_POSITION);
+    })(),
+  );
+
+  return {
+    destroy() {
+      unsubscribeNavigating();
+    },
+  };
+}
+
+export function scrollMemoryClearer(_node: HTMLElement, { routeStartsWith, beforeClear }: Options) {
+  const unsubscribeNavigating = navigating.subscribe((navigation) => {
+    // Forget scroll position from main page if going somewhere else.
+    if (navigation?.to && !navigation?.to.url.pathname.startsWith(routeStartsWith)) {
+      beforeClear?.();
+      sessionStorage.removeItem(SessionStorageKey.SCROLL_POSITION);
+    }
+  });
+
+  return {
+    destroy() {
+      unsubscribeNavigating();
+    },
+  };
+}

web/src/lib/actions/use-actions.ts

@@ -0,0 +1,67 @@
+/**
+ * @license Apache-2.0
+ * https://github.com/hperrin/svelte-material-ui/blob/master/packages/common/src/internal/useActions.ts
+ */
+
+export type SvelteActionReturnType<P> = {
+  update?: (newParams?: P) => void;
+  destroy?: () => void;
+} | void;
+
+export type SvelteHTMLActionType<P> = (node: HTMLElement, params?: P) => SvelteActionReturnType<P>;
+
+// eslint-disable-next-line @typescript-eslint/no-explicit-any
+export type HTMLActionEntry<P = any> = SvelteHTMLActionType<P> | [SvelteHTMLActionType<P>, P];
+
+export type HTMLActionArray = HTMLActionEntry[];
+
+export type SvelteSVGActionType<P> = (node: SVGElement, params?: P) => SvelteActionReturnType<P>;
+
+// eslint-disable-next-line @typescript-eslint/no-explicit-any
+export type SVGActionEntry<P = any> = SvelteSVGActionType<P> | [SvelteSVGActionType<P>, P];
+
+export type SVGActionArray = SVGActionEntry[];
+
+export type ActionArray = HTMLActionArray | SVGActionArray;
+
+export function useActions(node: HTMLElement | SVGElement, actions: ActionArray) {
+  const actionReturns: SvelteActionReturnType<unknown>[] = [];
+
+  if (actions) {
+    for (const actionEntry of actions) {
+      const action = Array.isArray(actionEntry) ? actionEntry[0] : actionEntry;
+      if (Array.isArray(actionEntry) && actionEntry.length > 1) {
+        actionReturns.push(action(node as HTMLElement & SVGElement, actionEntry[1]));
+      } else {
+        actionReturns.push(action(node as HTMLElement & SVGElement));
+      }
+    }
+  }
+
+  return {
+    update(actions: ActionArray) {
+      if ((actions?.length || 0) != actionReturns.length) {
+        throw new Error('You must not change the length of an actions array.');
+      }
+
+      if (actions) {
+        for (const [i, returnEntry] of actionReturns.entries()) {
+          if (returnEntry && returnEntry.update) {
+            const actionEntry = actions[i];
+            if (Array.isArray(actionEntry) && actionEntry.length > 1) {
+              returnEntry.update(actionEntry[1]);
+            } else {
+              returnEntry.update();
+            }
+          }
+        }
+      }
+    },
+
+    destroy() {
+      for (const returnEntry of actionReturns) {
+        returnEntry?.destroy?.();
+      }
+    },
+  };
+}

web/src/lib/components/layouts/user-page-layout.svelte

@@ -7,6 +7,7 @@
   import NavigationBar from '../shared-components/navigation-bar/navigation-bar.svelte';
   import SideBar from '../shared-components/side-bar/side-bar.svelte';
   import AdminSideBar from '../shared-components/side-bar/admin-side-bar.svelte';
+  import { useActions, type ActionArray } from '$lib/actions/use-actions';
   import type { Snippet } from 'svelte';
 
   interface Props {
@@ -16,6 +17,7 @@
     description?: string | undefined;
     scrollbar?: boolean;
     admin?: boolean;
+    use?: ActionArray;
     header?: Snippet;
     sidebar?: Snippet;
     buttons?: Snippet;
@@ -29,6 +31,7 @@
     description = undefined,
     scrollbar = true,
     admin = false,
+    use = [],
     header,
     sidebar,
     buttons,
@@ -73,7 +76,7 @@
       </div>
     {/if}
 
-    <div class="{scrollbarClass} scrollbar-stable absolute {hasTitleClass} w-full overflow-y-auto">
+    <div class="{scrollbarClass} scrollbar-stable absolute {hasTitleClass} w-full overflow-y-auto" use:useActions={use}>
       {@render children?.()}
     </div>
   </section>

web/src/lib/constants.ts

@@ -83,6 +83,11 @@ export enum QueryParameter {
   PATH = 'path',
 }
 
+export enum SessionStorageKey {
+  INFINITE_SCROLL_PAGE = 'infiniteScrollPage',
+  SCROLL_POSITION = 'scrollPosition',
+}
+
 export enum OpenSettingQueryParameterValue {
   OAUTH = 'oauth',
   JOB = 'job',

web/src/routes/(user)/albums/+page.svelte

@@ -1,5 +1,6 @@
 <script lang="ts">
   import type { PageData } from './$types';
+  import { scrollMemory } from '$lib/actions/scroll-memory';
   import { AlbumFilter, albumViewSettings } from '$lib/stores/preferences.store';
   import { createAlbumAndRedirect } from '$lib/utils/album-utils';
   import UserPageLayout from '$lib/components/layouts/user-page-layout.svelte';
@@ -8,6 +9,7 @@
   import EmptyPlaceholder from '$lib/components/shared-components/empty-placeholder.svelte';
   import GroupTab from '$lib/components/elements/group-tab.svelte';
   import SearchBar from '$lib/components/elements/search-bar.svelte';
+  import { AppRoute } from '$lib/constants';
   import { t } from 'svelte-i18n';
 
   interface Props {
@@ -20,7 +22,7 @@
   let albumGroups: string[] = $state([]);
 </script>
 
-<UserPageLayout title={data.meta.title}>
+<UserPageLayout title={data.meta.title} use={[[scrollMemory, { routeStartsWith: AppRoute.ALBUMS }]]}>
   {#snippet buttons()}
     <div class="flex place-items-center gap-2">
       <AlbumsControls {albumGroups} bind:searchQuery />

web/src/routes/(user)/albums/[albumId=id]/[[photos=photos]]/[[assetId=id]]/+page.svelte

@@ -1,5 +1,6 @@
 <script lang="ts">
   import { afterNavigate, goto, onNavigate } from '$app/navigation';
+  import { scrollMemoryClearer } from '$lib/actions/scroll-memory';
   import AlbumDescription from '$lib/components/album-page/album-description.svelte';
   import AlbumOptions from '$lib/components/album-page/album-options.svelte';
   import AlbumSummary from '$lib/components/album-page/album-summary.svelte';
@@ -430,7 +431,7 @@
   });
 </script>
 
-<div class="flex overflow-hidden">
+<div class="flex overflow-hidden" use:scrollMemoryClearer={{ routeStartsWith: AppRoute.ALBUMS }}>
   <div class="relative w-full shrink">
     {#if $isMultiSelectState}
       <AssetSelectControlBar assets={$selectedAssets} clearSelect={() => assetInteractionStore.clearMultiselect()}>

web/src/routes/(user)/people/+page.svelte

@@ -2,6 +2,7 @@
   import { goto } from '$app/navigation';
   import { page } from '$app/stores';
   import { focusTrap } from '$lib/actions/focus-trap';
+  import { scrollMemory } from '$lib/actions/scroll-memory';
   import Button from '$lib/components/elements/buttons/button.svelte';
   import LinkButton from '$lib/components/elements/buttons/link-button.svelte';
   import Icon from '$lib/components/elements/icon.svelte';
@@ -17,7 +18,7 @@
     notificationController,
     NotificationType,
   } from '$lib/components/shared-components/notification/notification';
-  import { ActionQueryParameterValue, AppRoute, QueryParameter } from '$lib/constants';
+  import { ActionQueryParameterValue, AppRoute, QueryParameter, SessionStorageKey } from '$lib/constants';
   import { locale } from '$lib/stores/preferences.store';
   import { websocketEvents } from '$lib/stores/websocket';
   import { handlePromiseError } from '$lib/utils';
@@ -50,6 +51,7 @@
   let showSetBirthDateModal = $state(false);
   let showMergeModal = $state(false);
   let personName = $state('');
+  let currentPage = $state(1);
   let nextPage = $state(data.people.hasNextPage ? 2 : null);
   let personMerge1 = $state<PersonResponseDto>();
   let personMerge2 = $state<PersonResponseDto>();
@@ -68,6 +70,7 @@
         handlePromiseError(searchPeopleElement.searchPeople(true, searchName));
       }
     }
+
     return websocketEvents.on('on_person_thumbnail', (personId: string) => {
       for (const person of people) {
         if (person.id === personId) {
@@ -77,6 +80,36 @@
     });
   });
 
+  const loadInitialScroll = () =>
+    new Promise<void>((resolve) => {
+      // Load up to previously loaded page when returning.
+      let newNextPage = sessionStorage.getItem(SessionStorageKey.INFINITE_SCROLL_PAGE);
+      if (newNextPage && nextPage) {
+        let startingPage = nextPage,
+          pagesToLoad = Number.parseInt(newNextPage) - nextPage;
+
+        if (pagesToLoad) {
+          handlePromiseError(
+            Promise.all(
+              Array.from({ length: pagesToLoad }).map((_, i) => {
+                return getAllPeople({ withHidden: true, page: startingPage + i });
+              }),
+            ).then((pages) => {
+              for (const page of pages) {
+                people = people.concat(page.people);
+              }
+              currentPage = startingPage + pagesToLoad - 1;
+              nextPage = pages.at(-1)?.hasNextPage ? startingPage + pagesToLoad : null;
+              resolve(); // wait until extra pages are loaded
+            }),
+          );
+        } else {
+          resolve();
+        }
+        sessionStorage.removeItem(SessionStorageKey.INFINITE_SCROLL_PAGE);
+      }
+    });
+
   const loadNextPage = async () => {
     if (!nextPage) {
       return;
@@ -85,6 +118,9 @@
     try {
       const { people: newPeople, hasNextPage } = await getAllPeople({ withHidden: true, page: nextPage });
       people = people.concat(newPeople);
+      if (nextPage !== null) {
+        currentPage = nextPage;
+      }
       nextPage = hasNextPage ? nextPage + 1 : null;
     } catch (error) {
       handleError(error, $t('errors.failed_to_load_people'));
@@ -323,6 +359,23 @@
 <UserPageLayout
   title={$t('people')}
   description={countVisiblePeople === 0 && !searchName ? undefined : `(${countVisiblePeople.toLocaleString($locale)})`}
+  use={[
+    [
+      scrollMemory,
+      {
+        routeStartsWith: AppRoute.PEOPLE,
+        beforeSave: () => {
+          if (currentPage) {
+            sessionStorage.setItem(SessionStorageKey.INFINITE_SCROLL_PAGE, currentPage.toString());
+          }
+        },
+        beforeClear: () => {
+          sessionStorage.removeItem(SessionStorageKey.INFINITE_SCROLL_PAGE);
+        },
+        beforeLoad: loadInitialScroll,
+      },
+    ],
+  ]}
 >
   {#snippet buttons()}
     {#if people.length > 0}

web/src/routes/(user)/people/[personId]/[[photos=photos]]/[[assetId=id]]/+page.svelte

@@ -1,6 +1,7 @@
 <script lang="ts">
   import { afterNavigate, goto } from '$app/navigation';
   import { page } from '$app/stores';
+  import { scrollMemoryClearer } from '$lib/actions/scroll-memory';
   import ImageThumbnail from '$lib/components/assets/thumbnail/image-thumbnail.svelte';
   import EditNameInput from '$lib/components/faces-page/edit-name-input.svelte';
   import MergeFaceSelector from '$lib/components/faces-page/merge-face-selector.svelte';
@@ -25,7 +26,7 @@
     NotificationType,
     notificationController,
   } from '$lib/components/shared-components/notification/notification';
-  import { AppRoute, PersonPageViewMode, QueryParameter } from '$lib/constants';
+  import { AppRoute, PersonPageViewMode, QueryParameter, SessionStorageKey } from '$lib/constants';
   import { createAssetInteractionStore } from '$lib/stores/asset-interaction.store';
   import { assetViewingStore } from '$lib/stores/asset-viewing.store';
   import { AssetStore } from '$lib/stores/assets.store';
@@ -164,7 +165,7 @@
         type: NotificationType.Info,
       });
 
-      await goto(previousRoute, { replaceState: true });
+      await goto(previousRoute);
     } catch (error) {
       handleError(error, $t('errors.unable_to_hide_person'));
     }
@@ -431,7 +432,15 @@
   {/if}
 </header>
 
-<main class="relative h-screen overflow-hidden bg-immich-bg tall:ml-4 pt-[var(--navbar-height)] dark:bg-immich-dark-bg">
+<main
+  class="relative h-screen overflow-hidden bg-immich-bg tall:ml-4 pt-[var(--navbar-height)] dark:bg-immich-dark-bg"
+  use:scrollMemoryClearer={{
+    routeStartsWith: AppRoute.PEOPLE,
+    beforeClear: () => {
+      sessionStorage.removeItem(SessionStorageKey.INFINITE_SCROLL_PAGE);
+    },
+  }}
+>
   {#key person.id}
     <AssetGrid
       enableRouting={true}