From 3a29294f9607af31864a1d9bb8f5967416cfdc07 Mon Sep 17 00:00:00 2001
From: patrick <patrickjaroszewski@protonmail.com>
Date: Mon, 17 Aug 2026 17:55:21 -0400
Subject: [PATCH] chore: clear the mechanical lint and type findings

Dead imports and locals removed, each blocks keyed, `any` narrowed to unknown.
Two context setters kept their calls and lost only the unused binding; the
settings redirect no longer awaits a parent whose data it discards. A leading
underscore now marks a binding that only holds a position.
---
 frontend/eslint.config.js                     | 13 +++++++-
 frontend/src/lib/api/auth.remote.ts           |  2 +-
 frontend/src/lib/api/library.remote.ts        |  2 +-
 .../lib/components/forms/book-delete.svelte   |  5 ----
 .../forms/device-create-form.svelte           |  2 +-
 .../forms/edit-book/edit-metadata.svelte      | 30 +++++++++----------
 .../forms/library-create-form.svelte          |  8 ++---
 .../lib/components/forms/login-form.svelte    |  4 +--
 .../lib/components/forms/signup-form.svelte   |  6 ++--
 .../components/layout/library-switcher.svelte |  2 +-
 .../lib/components/layout/search-form.svelte  | 10 +++----
 .../src/lib/components/view/book-grid.svelte  |  1 -
 .../src/lib/components/view/book-image.svelte |  6 ++--
 .../src/lib/components/view/book-table.svelte |  1 -
 .../lib/components/view/book-thumbnail.svelte |  5 ++--
 .../src/lib/components/view/filters.svelte    |  2 +-
 .../lib/components/view/sort-button.svelte    |  2 +-
 frontend/src/lib/schema/auth.ts               |  2 --
 frontend/src/lib/schema/author.ts             |  4 +--
 frontend/src/lib/schema/book.ts               |  2 +-
 frontend/src/lib/schema/publisher.ts          |  2 --
 frontend/src/lib/schema/tag.ts                |  2 --
 frontend/src/lib/server/api.ts                |  6 ++--
 .../src/lib/state/bookCollection.svelte.ts    |  2 +-
 .../src/lib/state/bookOperations.svelte.ts    |  2 +-
 frontend/src/lib/state/bookshelf.svelte.ts    |  8 ++---
 frontend/src/lib/state/library.svelte.ts      |  2 +-
 .../routes/(root)/(library)/+layout.svelte    |  2 +-
 .../(library)/book/[bookId]/+page.svelte      | 12 ++------
 frontend/src/routes/(root)/+layout.svelte     |  6 ++--
 .../src/routes/(root)/settings/+layout.svelte |  2 +-
 frontend/src/routes/(root)/settings/+page.ts  |  4 +--
 .../(root)/settings/devices/+page.svelte      |  2 +-
 .../(root)/settings/libraries/+page.svelte    |  2 +-
 frontend/src/routes/api/[...path]/+server.ts  |  2 +-
 frontend/src/routes/login/+page.svelte        |  2 --
 36 files changed, 76 insertions(+), 91 deletions(-)

diff --git a/frontend/eslint.config.js b/frontend/eslint.config.js
index 3d7c2e7..dc597a2 100644
--- a/frontend/eslint.config.js
+++ b/frontend/eslint.config.js
@@ -28,7 +28,18 @@ export default defineConfig(
 		rules: {
 			// typescript-eslint strongly recommend that you do not use the no-undef lint rule on TypeScript projects.
 			// see: https://typescript-eslint.io/troubleshooting/faqs/eslint/#i-get-errors-from-the-no-undef-rule-about-global-variables-not-being-defined-even-though-there-are-no-typescript-errors
-			'no-undef': 'off'
+			'no-undef': 'off',
+			// A leading underscore marks a binding that exists to hold a position — a callback
+			// parameter the signature requires, or the discarded half of a destructure.
+			'@typescript-eslint/no-unused-vars': [
+				'error',
+				{
+					argsIgnorePattern: '^_',
+					varsIgnorePattern: '^_',
+					caughtErrorsIgnorePattern: '^_',
+					destructuredArrayIgnorePattern: '^_'
+				}
+			]
 		}
 	},
 	{
diff --git a/frontend/src/lib/api/auth.remote.ts b/frontend/src/lib/api/auth.remote.ts
index 807347d..a147fb9 100644
--- a/frontend/src/lib/api/auth.remote.ts
+++ b/frontend/src/lib/api/auth.remote.ts
@@ -4,7 +4,7 @@ import { BACKEND_API_URL } from '$lib/server/config';
 import { invalid, redirect } from '@sveltejs/kit';
 
 export const login = form(loginSchema, async (data, issue) => {
-	const { cookies, locals } = getRequestEvent();
+	const { cookies } = getRequestEvent();
 
 	// Create URL-encoded form data
 	const formData = new URLSearchParams();
diff --git a/frontend/src/lib/api/library.remote.ts b/frontend/src/lib/api/library.remote.ts
index eeb119e..9e097fd 100644
--- a/frontend/src/lib/api/library.remote.ts
+++ b/frontend/src/lib/api/library.remote.ts
@@ -25,6 +25,6 @@ export const createLibrary = form(libraryCreateSchema, async (data) => {
 	return await response.json();
 });
 
-export const deleteLibrary = query('unchecked', async (data) => {
+export const deleteLibrary = query('unchecked', async (_data) => {
 	throw new Error('Not implemented');
 });
diff --git a/frontend/src/lib/components/forms/book-delete.svelte b/frontend/src/lib/components/forms/book-delete.svelte
index ffc91ce..134f207 100644
--- a/frontend/src/lib/components/forms/book-delete.svelte
+++ b/frontend/src/lib/components/forms/book-delete.svelte
@@ -3,8 +3,6 @@
 	import { Checkbox } from '$lib/components/ui/checkbox/index.js';
 	import { Button } from '$lib/components/ui/button/index.js';
 	import * as Dialog from '$lib/components/ui/dialog/index.js';
-	import { getBookSelectionState } from '$lib/state/bookSelection.svelte';
-	import { getBookOperationsState } from '$lib/state/bookOperations.svelte';
 
 	let {
 		open = $bindable(),
@@ -16,9 +14,6 @@
 		deleteFn: (deleteFiles: boolean) => void | Promise<void>;
 	} = $props();
 
-	const selectedState = getBookSelectionState();
-	const bookOps = getBookOperationsState();
-
 	let deleteFiles = $state(false);
 </script>
 
diff --git a/frontend/src/lib/components/forms/device-create-form.svelte b/frontend/src/lib/components/forms/device-create-form.svelte
index f1811c4..9860119 100644
--- a/frontend/src/lib/components/forms/device-create-form.svelte
+++ b/frontend/src/lib/components/forms/device-create-form.svelte
@@ -39,7 +39,7 @@
 			<Field.Field>
 				<Field.Label for="name">Device name</Field.Label>
 				<Input {...createDevice.fields.name.as('text')} placeholder="e.g. Kindle Paperwhite" />
-				{#each createDevice.fields.name.issues() ?? [] as issue}
+				{#each createDevice.fields.name.issues() ?? [] as issue, i (i)}
 					<Field.Error>{issue.message}</Field.Error>
 				{/each}
 			</Field.Field>
diff --git a/frontend/src/lib/components/forms/edit-book/edit-metadata.svelte b/frontend/src/lib/components/forms/edit-book/edit-metadata.svelte
index 45e149f..95e0654 100644
--- a/frontend/src/lib/components/forms/edit-book/edit-metadata.svelte
+++ b/frontend/src/lib/components/forms/edit-book/edit-metadata.svelte
@@ -128,7 +128,7 @@
 	<Field.Field class="col-span-full">
 		<Field.Label for="title">Title</Field.Label>
 		<Input {...updateBookMetadata.fields.title.as('text')} />
-		{#each updateBookMetadata.fields.title.issues() ?? [] as issue}
+		{#each updateBookMetadata.fields.title.issues() ?? [] as issue, i (i)}
 			<Field.Error>{issue.message}</Field.Error>
 		{/each}
 	</Field.Field>
@@ -136,7 +136,7 @@
 	<Field.Field>
 		<Field.Label for="subtitle">Subtitle</Field.Label>
 		<Input {...updateBookMetadata.fields.subtitle.as('text')} />
-		{#each updateBookMetadata.fields.subtitle.issues() ?? [] as issue}
+		{#each updateBookMetadata.fields.subtitle.issues() ?? [] as issue, i (i)}
 			<Field.Error>{issue.message}</Field.Error>
 		{/each}
 	</Field.Field>
@@ -144,7 +144,7 @@
 	<Field.Field>
 		<Field.Label for="edition">Edition</Field.Label>
 		<Input {...updateBookMetadata.fields.edition.as('number')} />
-		{#each updateBookMetadata.fields.edition.issues() ?? [] as issue}
+		{#each updateBookMetadata.fields.edition.issues() ?? [] as issue, i (i)}
 			<Field.Error>{issue.message}</Field.Error>
 		{/each}
 	</Field.Field>
@@ -152,7 +152,7 @@
 	<Field.Field>
 		<Field.Label for="series">Series</Field.Label>
 		<Input {...updateBookMetadata.fields.series.as('text')} />
-		{#each updateBookMetadata.fields.series.issues() ?? [] as issue}
+		{#each updateBookMetadata.fields.series.issues() ?? [] as issue, i (i)}
 			<Field.Error>{issue.message}</Field.Error>
 		{/each}
 	</Field.Field>
@@ -161,7 +161,7 @@
 		<Field.Field>
 			<Field.Label for="series_position">No.</Field.Label>
 			<Input {...updateBookMetadata.fields.series_position.as('text')} />
-			{#each updateBookMetadata.fields.series_position.issues() ?? [] as issue}
+			{#each updateBookMetadata.fields.series_position.issues() ?? [] as issue, i (i)}
 				<Field.Error>{issue.message}</Field.Error>
 			{/each}
 		</Field.Field>
@@ -169,7 +169,7 @@
 		<Field.Field>
 			<Field.Label for="language">Language</Field.Label>
 			<Input {...updateBookMetadata.fields.language.as('text')} />
-			{#each updateBookMetadata.fields.language.issues() ?? [] as issue}
+			{#each updateBookMetadata.fields.language.issues() ?? [] as issue, i (i)}
 				<Field.Error>{issue.message}</Field.Error>
 			{/each}
 		</Field.Field>
@@ -185,10 +185,10 @@
 			placeholder="Add an author"
 			class="min-h-10 p-2 text-sm"
 		/>
-		{#each authors as author}
+		{#each authors as author, i (i)}
 			<input class="hidden" {...updateBookMetadata.fields.authors.as('checkbox', author)} />
 		{/each}
-		{#each updateBookMetadata.fields.authors.issues() ?? [] as issue}
+		{#each updateBookMetadata.fields.authors.issues() ?? [] as issue, i (i)}
 			<Field.Error>{issue.message}</Field.Error>
 		{/each}
 	</Field.Field>
@@ -201,10 +201,10 @@
 			placeholder="Add a tag"
 			class="min-h-10 p-2 text-sm"
 		/>
-		{#each tags as tag}
+		{#each tags as tag, i (i)}
 			<input class="hidden" {...updateBookMetadata.fields.tags.as('checkbox', tag)} />
 		{/each}
-		{#each updateBookMetadata.fields.tags.issues() ?? [] as issue}
+		{#each updateBookMetadata.fields.tags.issues() ?? [] as issue, i (i)}
 			<Field.Error>{issue.message}</Field.Error>
 		{/each}
 	</Field.Field>
@@ -214,7 +214,7 @@
 	<Field.Field>
 		<Field.Label for="publisher">Publisher</Field.Label>
 		<Input {...updateBookMetadata.fields.publisher.as('text')} />
-		{#each updateBookMetadata.fields.publisher.issues() ?? [] as issue}
+		{#each updateBookMetadata.fields.publisher.issues() ?? [] as issue, i (i)}
 			<Field.Error>{issue.message}</Field.Error>
 		{/each}
 	</Field.Field>
@@ -223,7 +223,7 @@
 		<Field.Field>
 			<Field.Label for="published_date">Published</Field.Label>
 			<Input {...updateBookMetadata.fields.published_date.as('date')} />
-			{#each updateBookMetadata.fields.published_date.issues() ?? [] as issue}
+			{#each updateBookMetadata.fields.published_date.issues() ?? [] as issue, i (i)}
 				<Field.Error>{issue.message}</Field.Error>
 			{/each}
 		</Field.Field>
@@ -231,7 +231,7 @@
 		<Field.Field>
 			<Field.Label for="pages">Pages</Field.Label>
 			<Input {...updateBookMetadata.fields.pages.as('number')} />
-			{#each updateBookMetadata.fields.pages.issues() ?? [] as issue}
+			{#each updateBookMetadata.fields.pages.issues() ?? [] as issue, i (i)}
 				<Field.Error>{issue.message}</Field.Error>
 			{/each}
 		</Field.Field>
@@ -240,7 +240,7 @@
 	<Field.Field class="col-span-full">
 		<Field.Label for="identifiers">Identifiers</Field.Label>
 		<div class="flex flex-col gap-2">
-			{#each identifierKeys as _, idx}
+			{#each identifierKeys as _, idx (idx)}
 				<div class="grid grid-cols-[1fr_1.6fr_auto] gap-2">
 					<Input bind:value={identifierKeys[idx]} placeholder="ISBN, DOI…" />
 					<Input bind:value={identifierValues[idx]} placeholder="Value" />
@@ -271,7 +271,7 @@
 	<Field.Field class="col-span-full">
 		<Field.Label for="description" class="sr-only">Description</Field.Label>
 		<Textarea {...updateBookMetadata.fields.description.as('text')} rows={6} />
-		{#each updateBookMetadata.fields.description.issues() ?? [] as issue}
+		{#each updateBookMetadata.fields.description.issues() ?? [] as issue, i (i)}
 			<Field.Error>{issue.message}</Field.Error>
 		{/each}
 	</Field.Field>
diff --git a/frontend/src/lib/components/forms/library-create-form.svelte b/frontend/src/lib/components/forms/library-create-form.svelte
index b5e7460..9c93a4e 100644
--- a/frontend/src/lib/components/forms/library-create-form.svelte
+++ b/frontend/src/lib/components/forms/library-create-form.svelte
@@ -56,7 +56,7 @@
 							<Field.Field>
 								<Field.Label for="name">Library name</Field.Label>
 								<Input {...createLibrary.fields.name.as('text')} />
-								{#each createLibrary.fields.name.issues() ?? [] as issue}
+								{#each createLibrary.fields.name.issues() ?? [] as issue, i (i)}
 									<Field.Error>{issue.message}</Field.Error>
 								{/each}
 							</Field.Field>
@@ -73,7 +73,7 @@
 					<Field.Field>
 						<Field.Label for="description">Description</Field.Label>
 						<Textarea {...createLibrary.fields.description.as('text')} />
-						{#each createLibrary.fields.description.issues() ?? [] as issue}
+						{#each createLibrary.fields.description.issues() ?? [] as issue, i (i)}
 							<Field.Error>{issue.message}</Field.Error>
 						{/each}
 					</Field.Field>
@@ -82,7 +82,7 @@
 					<Field.Field>
 						<Field.Label for="root_path">Root Path</Field.Label>
 						<Input {...createLibrary.fields.root_path.as('text')} />
-						{#each createLibrary.fields.root_path.issues() ?? [] as issue}
+						{#each createLibrary.fields.root_path.issues() ?? [] as issue, i (i)}
 							<Field.Error>{issue.message}</Field.Error>
 						{/each}
 						<Field.Description class="text-xs">
@@ -94,7 +94,7 @@
 					<Field.Field>
 						<Field.Label for="path_template">Path Template</Field.Label>
 						<Input {...createLibrary.fields.path_template.as('text')} />
-						{#each createLibrary.fields.path_template.issues() ?? [] as issue}
+						{#each createLibrary.fields.path_template.issues() ?? [] as issue, i (i)}
 							<Field.Error>{issue.message}</Field.Error>
 						{/each}
 						<Field.Description class="text-xs">
diff --git a/frontend/src/lib/components/forms/login-form.svelte b/frontend/src/lib/components/forms/login-form.svelte
index a0c63d6..2b03ea0 100644
--- a/frontend/src/lib/components/forms/login-form.svelte
+++ b/frontend/src/lib/components/forms/login-form.svelte
@@ -21,7 +21,7 @@
 					<Field.Field>
 						<Field.Label for="email">Email</Field.Label>
 						<Input {...login.fields.email.as('email')} />
-						{#each login.fields.email.issues() ?? [] as issue}
+						{#each login.fields.email.issues() ?? [] as issue, i (i)}
 							<Field.Error>{issue.message}</Field.Error>
 						{/each}
 					</Field.Field>
@@ -30,7 +30,7 @@
 					<Field.Field>
 						<Field.Label for="password">Password</Field.Label>
 						<Input {...login.fields.password.as('password')} />
-						{#each login.fields.password.issues() ?? [] as issue}
+						{#each login.fields.password.issues() ?? [] as issue, i (i)}
 							<Field.Error>{issue.message}</Field.Error>
 						{/each}
 					</Field.Field>
diff --git a/frontend/src/lib/components/forms/signup-form.svelte b/frontend/src/lib/components/forms/signup-form.svelte
index c9c04f2..e9f8ba3 100644
--- a/frontend/src/lib/components/forms/signup-form.svelte
+++ b/frontend/src/lib/components/forms/signup-form.svelte
@@ -47,7 +47,7 @@
 					<Field.Field>
 						<Field.Label for="email">Email</Field.Label>
 						<Input {...signup.fields.email.as('email')} />
-						{#each signup.fields.email.issues() ?? [] as issue}
+						{#each signup.fields.email.issues() ?? [] as issue, i (i)}
 							<Field.Error>{issue.message}</Field.Error>
 						{/each}
 					</Field.Field>
@@ -56,7 +56,7 @@
 					<Field.Field>
 						<Field.Label for="password">Password</Field.Label>
 						<Input {...signup.fields.password.as('password')} />
-						{#each signup.fields.password.issues() ?? [] as issue}
+						{#each signup.fields.password.issues() ?? [] as issue, i (i)}
 							<Field.Error>{issue.message}</Field.Error>
 						{/each}
 					</Field.Field>
@@ -65,7 +65,7 @@
 					<Field.Field>
 						<Field.Label for="confirmPassword">Confirm Password</Field.Label>
 						<Input {...signup.fields.confirmPassword.as('password')} />
-						{#each signup.fields.confirmPassword.issues() ?? [] as issue}
+						{#each signup.fields.confirmPassword.issues() ?? [] as issue, i (i)}
 							<Field.Error>{issue.message}</Field.Error>
 						{/each}
 					</Field.Field>
diff --git a/frontend/src/lib/components/layout/library-switcher.svelte b/frontend/src/lib/components/layout/library-switcher.svelte
index c02db2c..7ac5446 100644
--- a/frontend/src/lib/components/layout/library-switcher.svelte
+++ b/frontend/src/lib/components/layout/library-switcher.svelte
@@ -3,7 +3,7 @@
 	import * as Sidebar from '$lib/components/ui/sidebar/index.js';
 	import { useSidebar } from '$lib/components/ui/sidebar/index.js';
 	import { Badge } from '$lib/components/ui/badge/index.js';
-	import { getLibraryState, LibraryState } from '$lib/state/library.svelte';
+	import { getLibraryState } from '$lib/state/library.svelte';
 	import { LIBRARY_ICONS } from '$lib/components/ui/icon-picker/index.js';
 	import ChevronsUpDownIcon from '@lucide/svelte/icons/chevrons-up-down';
 	import PlusIcon from '@lucide/svelte/icons/plus';
diff --git a/frontend/src/lib/components/layout/search-form.svelte b/frontend/src/lib/components/layout/search-form.svelte
index fdc3c5a..b7f03f8 100644
--- a/frontend/src/lib/components/layout/search-form.svelte
+++ b/frontend/src/lib/components/layout/search-form.svelte
@@ -53,9 +53,9 @@
 		}
 	}
 
-	function handleClick(e: any) {
+	function handleClick(e: Event & { currentTarget: HTMLElement }) {
 		open = true;
-		e.target.blur();
+		e.currentTarget.blur();
 	}
 </script>
 
@@ -93,7 +93,7 @@
 		</div>
 	{:else}
 		<Command.List class="max-h-[600px]">
-			{#if searchResult?.items.length > 0}
+			{#if (searchResult?.items?.length ?? 0) > 0}
 				<Command.Group heading="Books">
 					{#each searchResult?.items as book (book.id)}
 						<Command.Item
@@ -121,7 +121,7 @@
 									{#if book.authors.length > 0}
 										<span class="line-clamp-1 w-full text-sm text-muted-foreground">
 											by
-											{#each book.authors as author}
+											{#each book.authors as author (author.id)}
 												<a
 													href="{resolve('/(root)/(library)/library/[libraryId]/view', {
 														libraryId: String(libraryState.activeLibrary!.id)
@@ -132,7 +132,7 @@
 										</span>
 									{/if}
 									<div class="mt-1 ml-[-1.5] flex">
-										{#each book.tags as tag}
+										{#each book.tags as tag (tag.id)}
 											<Badge class="scale-75">{tag.name}</Badge>
 										{/each}
 									</div>
diff --git a/frontend/src/lib/components/view/book-grid.svelte b/frontend/src/lib/components/view/book-grid.svelte
index e3220c2..0240f4a 100644
--- a/frontend/src/lib/components/view/book-grid.svelte
+++ b/frontend/src/lib/components/view/book-grid.svelte
@@ -4,7 +4,6 @@
 
 	import type { Book } from '$lib/schema';
 	import BookThumbnail from './book-thumbnail.svelte';
-	import { goto } from '$app/navigation';
 	import { getBookSelectionState } from '$lib/state/bookSelection.svelte';
 	import { getBookOperationsState } from '$lib/state/bookOperations.svelte';
 	import { getLibraryState } from '$lib/state/library.svelte';
diff --git a/frontend/src/lib/components/view/book-image.svelte b/frontend/src/lib/components/view/book-image.svelte
index ff202c9..26db4ee 100644
--- a/frontend/src/lib/components/view/book-image.svelte
+++ b/frontend/src/lib/components/view/book-image.svelte
@@ -1,8 +1,10 @@
 <script>
 	let { src, fallback = '/images/default_cover.jpg', class: className = '' } = $props();
 
-	async function handleError(e) {
-		e.target.src = fallback;
+	/** @param {Event} e */
+	function handleError(e) {
+		const img = /** @type {HTMLImageElement} */ (e.currentTarget);
+		img.src = fallback;
 	}
 </script>
 
diff --git a/frontend/src/lib/components/view/book-table.svelte b/frontend/src/lib/components/view/book-table.svelte
index f0831b0..918a6a8 100644
--- a/frontend/src/lib/components/view/book-table.svelte
+++ b/frontend/src/lib/components/view/book-table.svelte
@@ -2,7 +2,6 @@
 	import { resolve } from '$app/paths';
 	import * as Table from '$lib/components/ui/table/index';
 	import * as DropdownMenu from '$lib/components/ui/dropdown-menu/index';
-	import * as Tooltip from '$lib/components/ui/tooltip/index';
 	import { Checkbox } from '$lib/components/ui/checkbox/index';
 	import { Badge } from '$lib/components/ui/badge/index';
 	import { buttonVariants } from '$lib/components/ui/button/index.js';
diff --git a/frontend/src/lib/components/view/book-thumbnail.svelte b/frontend/src/lib/components/view/book-thumbnail.svelte
index 762d01e..87d989b 100644
--- a/frontend/src/lib/components/view/book-thumbnail.svelte
+++ b/frontend/src/lib/components/view/book-thumbnail.svelte
@@ -2,12 +2,11 @@
 	import { resolve } from '$app/paths';
 	import BookImage from './book-image.svelte';
 	import GeneratedCover from './generated-cover.svelte';
-	import { Progress } from '$lib/components/ui/progress/index';
 	import { getLibraryState } from '$lib/state/library.svelte';
 	import { getBookSelectionState } from '$lib/state/bookSelection.svelte';
 	import type { Book } from '$lib/schema';
 
-	let { book, class: className = '', ...rest }: { book: Book; class?: string } = $props();
+	let { book, class: className = '' }: { book: Book; class?: string } = $props();
 
 	const selectionState = getBookSelectionState();
 	const libraryState = getLibraryState();
@@ -78,7 +77,7 @@
 
 	<!-- Authors list -->
 	<p class="line-clamp-1 w-full text-xs text-muted-foreground">
-		{#each book.authors as author}
+		{#each book.authors as author (author.id)}
 			<a
 				href="{resolve('/(root)/(library)/library/[libraryId]/view', {
 					libraryId: String(libraryState.activeLibrary?.id ?? '')
diff --git a/frontend/src/lib/components/view/filters.svelte b/frontend/src/lib/components/view/filters.svelte
index 2dc9ca3..49cba57 100644
--- a/frontend/src/lib/components/view/filters.svelte
+++ b/frontend/src/lib/components/view/filters.svelte
@@ -30,7 +30,7 @@
 			<Collapsible.Content class="h-full max-h-128 overflow-y-auto">
 				<Sidebar.GroupContent>
 					<Sidebar.Menu>
-						{#each filter.items as item, index (item.id)}
+						{#each filter.items as item (item.id)}
 							<Sidebar.MenuItem
 								onclick={() => bookCollection.toggleFilter(filter.value, item.id.toString())}
 							>
diff --git a/frontend/src/lib/components/view/sort-button.svelte b/frontend/src/lib/components/view/sort-button.svelte
index fc7a056..e1f91f8 100644
--- a/frontend/src/lib/components/view/sort-button.svelte
+++ b/frontend/src/lib/components/view/sort-button.svelte
@@ -25,7 +25,7 @@
 					</DropdownMenu.Trigger>
 					<DropdownMenu.Content class="w-40">
 						<DropdownMenu.Group>
-							{#each bookCollection.sortOptions as sortProp}
+							{#each bookCollection.sortOptions as sortProp (sortProp.value)}
 								<DropdownMenu.Item
 									onSelect={() => bookCollection.updateSort(sortProp.value)}
 									class={bookCollection.orderBy === sortProp.value ? 'bg-muted' : ''}
diff --git a/frontend/src/lib/schema/auth.ts b/frontend/src/lib/schema/auth.ts
index 40dc882..dfc4b6a 100644
--- a/frontend/src/lib/schema/auth.ts
+++ b/frontend/src/lib/schema/auth.ts
@@ -4,8 +4,6 @@ const emailSchema = z
 	.email('Please enter a valid email address')
 	.max(255, 'Email address cannot exceed 255 characters');
 
-const usernameSchema = z.string().min(1, 'Email is required');
-
 const basePasswordSchema = z.string().min(1, 'Password is required');
 
 const strongPasswordSchema = z.string().min(8, 'Password must be at least 8 characters');
diff --git a/frontend/src/lib/schema/author.ts b/frontend/src/lib/schema/author.ts
index fa8ece8..8173830 100644
--- a/frontend/src/lib/schema/author.ts
+++ b/frontend/src/lib/schema/author.ts
@@ -1,7 +1,5 @@
-import { z } from 'zod';
-
 import type { components } from './openapi/schema';
-import { commonQuerySchema, stringArrayCoerce, stringCoerce } from './common';
+import { commonQuerySchema, stringArrayCoerce } from './common';
 
 export type Author = components['schemas']['AuthorRead'];
 
diff --git a/frontend/src/lib/schema/book.ts b/frontend/src/lib/schema/book.ts
index 83ec697..d4286e3 100644
--- a/frontend/src/lib/schema/book.ts
+++ b/frontend/src/lib/schema/book.ts
@@ -67,7 +67,7 @@ const identifiersSchema = z
 	.transform((str, ctx) => {
 		try {
 			return JSON.parse(str);
-		} catch (e) {
+		} catch {
 			ctx.addIssue({
 				code: 'custom',
 				message: 'Must be a valid JSON string'
diff --git a/frontend/src/lib/schema/publisher.ts b/frontend/src/lib/schema/publisher.ts
index 87666d4..3cfe56e 100644
--- a/frontend/src/lib/schema/publisher.ts
+++ b/frontend/src/lib/schema/publisher.ts
@@ -1,5 +1,3 @@
-import { z } from 'zod';
-
 import type { components } from './openapi/schema';
 import { commonQuerySchema, stringArrayCoerce } from './common';
 
diff --git a/frontend/src/lib/schema/tag.ts b/frontend/src/lib/schema/tag.ts
index 8908432..457a078 100644
--- a/frontend/src/lib/schema/tag.ts
+++ b/frontend/src/lib/schema/tag.ts
@@ -1,5 +1,3 @@
-import { z } from 'zod';
-
 import type { components } from './openapi/schema';
 import { commonQuerySchema, stringArrayCoerce } from './common';
 
diff --git a/frontend/src/lib/server/api.ts b/frontend/src/lib/server/api.ts
index 2f7adfa..a9eeaf3 100644
--- a/frontend/src/lib/server/api.ts
+++ b/frontend/src/lib/server/api.ts
@@ -21,7 +21,7 @@ export class ApiClient {
 		return this.request(endpoint);
 	}
 
-	async post(endpoint: string, data: any): Promise<Response> {
+	async post(endpoint: string, data: unknown): Promise<Response> {
 		return this.request(endpoint, {
 			method: 'POST',
 			headers: {
@@ -48,7 +48,7 @@ export class ApiClient {
 		});
 	}
 
-	async put(endpoint: string, data: any): Promise<Response> {
+	async put(endpoint: string, data: unknown): Promise<Response> {
 		return this.request(endpoint, {
 			method: 'PUT',
 			headers: {
@@ -71,7 +71,7 @@ export class ApiClient {
 		});
 	}
 
-	async patch(endpoint: string, data: any): Promise<Response> {
+	async patch(endpoint: string, data: unknown): Promise<Response> {
 		return this.request(endpoint, {
 			method: 'PATCH',
 			headers: {
diff --git a/frontend/src/lib/state/bookCollection.svelte.ts b/frontend/src/lib/state/bookCollection.svelte.ts
index 886a33b..20d2af2 100644
--- a/frontend/src/lib/state/bookCollection.svelte.ts
+++ b/frontend/src/lib/state/bookCollection.svelte.ts
@@ -1,5 +1,5 @@
 import { getContext, setContext } from 'svelte';
-import { goto, pushState, replaceState } from '$app/navigation';
+import { goto, replaceState } from '$app/navigation';
 import type { Book, DynamicFilterData, FilterOption, PaginatedResponse } from '$lib/schema';
 import { page } from '$app/state';
 import { BookOperationsState } from './bookOperations.svelte';
diff --git a/frontend/src/lib/state/bookOperations.svelte.ts b/frontend/src/lib/state/bookOperations.svelte.ts
index 05976e7..49bc5d8 100644
--- a/frontend/src/lib/state/bookOperations.svelte.ts
+++ b/frontend/src/lib/state/bookOperations.svelte.ts
@@ -16,7 +16,7 @@ export class BookOperationsState {
 	// Delete dialog related state
 	deleteDialogOpen = $state(false);
 	deleteDialogTitle = $state('Delete books?');
-	deleteFn = $state((deleteFiles: boolean) => {});
+	deleteFn = $state((_deleteFiles: boolean) => {});
 
 	// Edit dialog related state
 	editDialogOpen = $state(false);
diff --git a/frontend/src/lib/state/bookshelf.svelte.ts b/frontend/src/lib/state/bookshelf.svelte.ts
index 907a584..def7e1a 100644
--- a/frontend/src/lib/state/bookshelf.svelte.ts
+++ b/frontend/src/lib/state/bookshelf.svelte.ts
@@ -1,4 +1,4 @@
-import { goto, invalidate } from '$app/navigation';
+import { invalidate } from '$app/navigation';
 import { addBooksToShelf, createBookshelf, listBookshelves, removeBooksFromShelf } from '$lib/api';
 import type { Book, Bookshelf } from '$lib/schema';
 import { getContext, setContext } from 'svelte';
@@ -22,7 +22,7 @@ export class BookshelfState {
 
 	async fetchBookshelves(libraryId: string) {
 		try {
-			let paginatedBookshelves = await listBookshelves({
+			const paginatedBookshelves = await listBookshelves({
 				libraries: [libraryId]
 			});
 
@@ -34,7 +34,7 @@ export class BookshelfState {
 
 	async addBookshelf(name: string, libraryId?: string | number, booksToAdd?: string[] | number[]) {
 		try {
-			let bookshelf = await createBookshelf({
+			const bookshelf = await createBookshelf({
 				title: name,
 				library_id: libraryId,
 				book_ids: booksToAdd
@@ -133,7 +133,7 @@ export class BookshelfState {
 						decrementBy++;
 					}
 				});
-				return { ...shelf, total: shelf.total - decrementBy };
+				return { ...shelf, total: (shelf.total ?? 0) - decrementBy };
 			}
 			return shelf;
 		});
diff --git a/frontend/src/lib/state/library.svelte.ts b/frontend/src/lib/state/library.svelte.ts
index 66d6009..441c63a 100644
--- a/frontend/src/lib/state/library.svelte.ts
+++ b/frontend/src/lib/state/library.svelte.ts
@@ -1,6 +1,6 @@
 import { resolve } from '$app/paths';
 import { browser } from '$app/environment';
-import { goto, invalidate } from '$app/navigation';
+import { goto } from '$app/navigation';
 import { page } from '$app/state';
 import { deleteLibrary } from '$lib/api';
 import type { Library } from '$lib/schema';
diff --git a/frontend/src/routes/(root)/(library)/+layout.svelte b/frontend/src/routes/(root)/(library)/+layout.svelte
index 8ef251b..eeba899 100644
--- a/frontend/src/routes/(root)/(library)/+layout.svelte
+++ b/frontend/src/routes/(root)/(library)/+layout.svelte
@@ -1,7 +1,7 @@
 <script lang="ts">
 	import BookDelete from '$lib/components/forms/book-delete.svelte';
 	import { BookEdit } from '$lib/components/forms/edit-book';
-	import { getBookOperationsState, setBookOperationsState } from '$lib/state/bookOperations.svelte';
+	import { getBookOperationsState } from '$lib/state/bookOperations.svelte';
 	import { getLibraryState } from '$lib/state/library.svelte';
 	import { setBookSelectionState } from '$lib/state/bookSelection.svelte';
 	import type { Snippet } from 'svelte';
diff --git a/frontend/src/routes/(root)/(library)/book/[bookId]/+page.svelte b/frontend/src/routes/(root)/(library)/book/[bookId]/+page.svelte
index b5f6bb4..cd489b9 100644
--- a/frontend/src/routes/(root)/(library)/book/[bookId]/+page.svelte
+++ b/frontend/src/routes/(root)/(library)/book/[bookId]/+page.svelte
@@ -28,22 +28,16 @@
 	import { getBookOperationsState } from '$lib/state/bookOperations.svelte.js';
 	import { getBookshelfState } from '$lib/state/bookshelf.svelte.js';
 	import { getLibraryState } from '$lib/state/library.svelte.js';
-	import { Progress } from '$lib/components/ui/progress/index.js';
 	import * as Accordion from '$lib/components/ui/accordion/index.js';
 	import * as Table from '$lib/components/ui/table/index.js';
 	import * as AlertDialog from '$lib/components/ui/alert-dialog/index.js';
 	import ShelfCreateDialog from '$lib/components/forms/shelf-create-dialog.svelte';
-	import { untrack } from 'svelte';
 
 	let { data } = $props();
 
-	// Seeded once, then kept in sync by the effect below — untrack says so
-	// explicitly rather than capturing the initial value and warning about it.
-	let book = $state(untrack(() => data.book));
-
-	$effect(() => {
-		book = data.book;
-	});
+	// Follows the loaded book, and stays assignable so an edit can update it locally
+	// until the next navigation supplies a fresh one.
+	let book = $derived(data.book);
 
 	const bookOps = getBookOperationsState();
 	const libraryState = getLibraryState();
diff --git a/frontend/src/routes/(root)/+layout.svelte b/frontend/src/routes/(root)/+layout.svelte
index 901efb6..356eaec 100644
--- a/frontend/src/routes/(root)/+layout.svelte
+++ b/frontend/src/routes/(root)/+layout.svelte
@@ -1,9 +1,7 @@
 <script lang="ts">
-	import { listBookshelves } from '$lib/api';
 	import AppSidebar from '$lib/components/layout/app-sidebar.svelte';
 	import SiteHeader from '$lib/components/layout/site-header.svelte';
 	import UploadTray from '$lib/components/layout/upload-tray.svelte';
-	import { Loading } from '$lib/components/ui/command';
 	import * as Sidebar from '$lib/components/ui/sidebar/index.js';
 	import type { Library, PaginatedResponse } from '$lib/schema';
 	import { setBookOperationsState } from '$lib/state/bookOperations.svelte';
@@ -28,8 +26,8 @@
 	// init. `untrack` says that explicitly, instead of silently capturing the
 	// initial value and warning about it.
 	const libraryState = setLibraryState(untrack(() => data.libraries.items));
-	const bookshelfState = setBookshelfState();
-	const bookOps = setBookOperationsState(libraryState.activeLibrary!.id);
+	setBookshelfState();
+	setBookOperationsState(libraryState.activeLibrary!.id);
 	const theme = setThemeState(untrack(() => data.theme));
 
 	// Set here rather than beside the upload dialog so a running import survives
diff --git a/frontend/src/routes/(root)/settings/+layout.svelte b/frontend/src/routes/(root)/settings/+layout.svelte
index 048650e..12bd9fb 100644
--- a/frontend/src/routes/(root)/settings/+layout.svelte
+++ b/frontend/src/routes/(root)/settings/+layout.svelte
@@ -41,7 +41,7 @@
 		     of libraries; the row above it is overflow-hidden, so without this a
 		     long list is clipped rather than reachable. -->
 		<nav class="flex w-48 shrink-0 flex-col gap-1 overflow-y-auto">
-			{#each items as item}
+			{#each items as item (item.routeId)}
 				<a
 					href={resolve(item.routeId)}
 					class="rounded-md px-3 py-2 text-sm font-medium transition-colors hover:bg-muted {page
diff --git a/frontend/src/routes/(root)/settings/+page.ts b/frontend/src/routes/(root)/settings/+page.ts
index eba8368..f8927e7 100644
--- a/frontend/src/routes/(root)/settings/+page.ts
+++ b/frontend/src/routes/(root)/settings/+page.ts
@@ -1,8 +1,6 @@
 import { redirect } from '@sveltejs/kit';
 
-export async function load({ parent }) {
-	const { libraries } = await parent();
-
+export async function load() {
 	// Immediately redirect to the account settings
 	redirect(303, `/settings/account`);
 }
diff --git a/frontend/src/routes/(root)/settings/devices/+page.svelte b/frontend/src/routes/(root)/settings/devices/+page.svelte
index fb29e89..bc555cb 100644
--- a/frontend/src/routes/(root)/settings/devices/+page.svelte
+++ b/frontend/src/routes/(root)/settings/devices/+page.svelte
@@ -130,7 +130,7 @@
 					</Table.Row>
 				</Table.Header>
 				<Table.Body>
-					{#each data.devices as device}
+					{#each data.devices as device (device.id)}
 						{@const isVisible = visibleApiKeys.has(String(device.id))}
 						<Table.Row class="h-14">
 							<Table.Cell class="pl-4 font-medium">
diff --git a/frontend/src/routes/(root)/settings/libraries/+page.svelte b/frontend/src/routes/(root)/settings/libraries/+page.svelte
index c3e03be..bd203da 100644
--- a/frontend/src/routes/(root)/settings/libraries/+page.svelte
+++ b/frontend/src/routes/(root)/settings/libraries/+page.svelte
@@ -31,7 +31,7 @@
 				</Table.Row>
 			</Table.Header>
 			<Table.Body>
-				{#each libraryState.libraries as library}
+				{#each libraryState.libraries as library (library.id)}
 					<Table.Row class="h-14">
 						<Table.Cell class="w-16 pl-4 text-center text-lg font-semibold"
 							>{library.name[0]}</Table.Cell
diff --git a/frontend/src/routes/api/[...path]/+server.ts b/frontend/src/routes/api/[...path]/+server.ts
index 948f6b9..88b827f 100644
--- a/frontend/src/routes/api/[...path]/+server.ts
+++ b/frontend/src/routes/api/[...path]/+server.ts
@@ -137,7 +137,7 @@ export const DELETE: RequestHandler = async ({ params, locals, fetch, request, u
 		const headers = prepareRequest(locals, request);
 
 		// DELETE may or may not have a body
-		let options: RequestInit = {
+		const options: RequestInit = {
 			method: 'DELETE',
 			headers
 		};
diff --git a/frontend/src/routes/login/+page.svelte b/frontend/src/routes/login/+page.svelte
index a1914b5..35d864e 100644
--- a/frontend/src/routes/login/+page.svelte
+++ b/frontend/src/routes/login/+page.svelte
@@ -1,9 +1,7 @@
 <script lang="ts">
-	import { replaceState } from '$app/navigation';
 	import LoginForm from '$lib/components/forms/login-form.svelte';
 	import SignupForm from '$lib/components/forms/signup-form.svelte';
 	import * as Tabs from '$lib/components/ui/tabs/index.js';
-	import { redirect } from '@sveltejs/kit';
 
 	let tabValue = $state('login');
 </script>