From ff7dca35f5c6af2a514b041a33fa4f2247aecfa0 Mon Sep 17 00:00:00 2001
From: Michel Heusschen <59014050+michelheusschen@users.noreply.github.com>
Date: Sat, 14 Feb 2026 21:31:04 +0100
Subject: [PATCH] perf(web): speed up asset selection (#26216)

---
 .../lib/stores/asset-interaction.svelte.ts    | 20 ++++++++-----------
 web/src/lib/utils/asset-utils.ts              |  7 ++++---
 2 files changed, 12 insertions(+), 15 deletions(-)

diff --git a/web/src/lib/stores/asset-interaction.svelte.ts b/web/src/lib/stores/asset-interaction.svelte.ts
index 9cfc1b2c8e..817354e619 100644
--- a/web/src/lib/stores/asset-interaction.svelte.ts
+++ b/web/src/lib/stores/asset-interaction.svelte.ts
@@ -1,14 +1,15 @@
 import type { TimelineAsset } from '$lib/managers/timeline-manager/types';
 import { user } from '$lib/stores/user.store';
 import { AssetVisibility, type UserAdminResponseDto } from '@immich/sdk';
-import { SvelteSet } from 'svelte/reactivity';
+import { SvelteMap, SvelteSet } from 'svelte/reactivity';
 import { fromStore } from 'svelte/store';
 
 export class AssetInteraction {
-  selectedAssets = $state<TimelineAsset[]>([]);
+  private selectedAssetsMap = new SvelteMap<string, TimelineAsset>();
+  selectedAssets = $derived(Array.from(this.selectedAssetsMap.values()));
   selectAll = $state(false);
   hasSelectedAsset(assetId: string) {
-    return this.selectedAssets.some((asset) => asset.id === assetId);
+    return this.selectedAssetsMap.has(assetId);
   }
   selectedGroup = new SvelteSet<string>();
   assetSelectionCandidates = $state<TimelineAsset[]>([]);
@@ -16,7 +17,7 @@ export class AssetInteraction {
     return this.assetSelectionCandidates.some((asset) => asset.id === assetId);
   }
   assetSelectionStart = $state<TimelineAsset | null>(null);
-  selectionActive = $derived(this.selectedAssets.length > 0);
+  selectionActive = $derived(this.selectedAssetsMap.size > 0);
 
   private user = fromStore<UserAdminResponseDto | undefined>(user);
   private userId = $derived(this.user.current?.id);
@@ -27,9 +28,7 @@ export class AssetInteraction {
   isAllUserOwned = $derived(this.selectedAssets.every((asset) => asset.ownerId === this.userId));
 
   selectAsset(asset: TimelineAsset) {
-    if (!this.hasSelectedAsset(asset.id)) {
-      this.selectedAssets.push(asset);
-    }
+    this.selectedAssetsMap.set(asset.id, asset);
   }
 
   selectAssets(assets: TimelineAsset[]) {
@@ -39,10 +38,7 @@ export class AssetInteraction {
   }
 
   removeAssetFromMultiselectGroup(assetId: string) {
-    const index = this.selectedAssets.findIndex((a) => a.id == assetId);
-    if (index !== -1) {
-      this.selectedAssets.splice(index, 1);
-    }
+    this.selectedAssetsMap.delete(assetId);
   }
 
   addGroupToMultiselectGroup(group: string) {
@@ -69,7 +65,7 @@ export class AssetInteraction {
     this.selectAll = false;
 
     // Multi-selection
-    this.selectedAssets = [];
+    this.selectedAssetsMap.clear();
     this.selectedGroup.clear();
 
     // Range selection
diff --git a/web/src/lib/utils/asset-utils.ts b/web/src/lib/utils/asset-utils.ts
index 84e386d620..47df967844 100644
--- a/web/src/lib/utils/asset-utils.ts
+++ b/web/src/lib/utils/asset-utils.ts
@@ -4,7 +4,6 @@ import { authManager } from '$lib/managers/auth-manager.svelte';
 import { downloadManager } from '$lib/managers/download-manager.svelte';
 import { TimelineManager } from '$lib/managers/timeline-manager/timeline-manager.svelte';
 import type { TimelineAsset } from '$lib/managers/timeline-manager/types';
-import { assetsSnapshot } from '$lib/managers/timeline-manager/utils.svelte';
 import { Route } from '$lib/route';
 import type { AssetInteraction } from '$lib/stores/asset-interaction.svelte';
 import { preferences } from '$lib/stores/user.store';
@@ -443,13 +442,15 @@ export const selectAllAssets = async (timelineManager: TimelineManager, assetInt
 
   try {
     for (const monthGroup of timelineManager.months) {
-      await timelineManager.loadMonthGroup(monthGroup.yearMonth);
+      if (!monthGroup.isLoaded) {
+        await timelineManager.loadMonthGroup(monthGroup.yearMonth);
+      }
 
       if (!assetInteraction.selectAll) {
         assetInteraction.clearMultiselect();
         break; // Cancelled
       }
-      assetInteraction.selectAssets(assetsSnapshot([...monthGroup.assetsIterator()]));
+      assetInteraction.selectAssets([...monthGroup.assetsIterator()]);
 
       for (const dateGroup of monthGroup.dayGroups) {
         assetInteraction.addGroupToMultiselectGroup(dateGroup.groupTitle);