feat(SampleList): remove text loader and add a prop isLoading

src/entities/Font/ui/FontVirtualList/FontVirtualList.svelte

@@ -4,8 +4,12 @@
     - Handles font registration with the manager
 -->
 <script lang="ts" generics="T extends UnifiedFont">
-import { VirtualList } from '$shared/ui';
+import {
+    Skeleton,
+    VirtualList,
+} from '$shared/ui';
 import type { ComponentProps } from 'svelte';
+import { fade } from 'svelte/transition';
 import { getFontUrl } from '../../lib';
 import type { FontConfigRequest } from '../../model';
 import {
@@ -13,13 +17,42 @@ import {
     appliedFontsManager,
 } from '../../model';
 
-interface Props extends Omit<ComponentProps<typeof VirtualList<T>>, 'onVisibleItemsChange'> {
+interface Props extends
+    Omit<
+        ComponentProps<typeof VirtualList<T>>,
+        'onVisibleItemsChange'
+    >
+{
+    /**
+     * Callback for when visible items change
+     */
     onVisibleItemsChange?: (items: T[]) => void;
+    /**
+     * Callback for when near bottom is reached
+     */
     onNearBottom?: (lastVisibleIndex: number) => void;
+    /**
+     * Weight of the font
+     */
+    /**
+     * Weight of the font
+     */
     weight: number;
+    /**
+     * Whether the list is in a loading state
+     */
+    isLoading?: boolean;
 }
 
-let { items, children, onVisibleItemsChange, onNearBottom, weight, ...rest }: Props = $props();
+let {
+    items,
+    children,
+    onVisibleItemsChange,
+    onNearBottom,
+    weight,
+    isLoading = false,
+    ...rest
+}: Props = $props();
 
 function handleInternalVisibleChange(visibleItems: T[]) {
     const configs: FontConfigRequest[] = [];
@@ -50,13 +83,31 @@ function handleNearBottom(lastVisibleIndex: number) {
 }
 </script>
 
-<VirtualList
-    {items}
-    {...rest}
-    onVisibleItemsChange={handleInternalVisibleChange}
-    onNearBottom={handleNearBottom}
->
-    {#snippet children(scope)}
-        {@render children(scope)}
-    {/snippet}
-</VirtualList>
+{#key isLoading}
+    <div class="relative w-full h-full" transition:fade={{ duration: 300 }}>
+        {#if isLoading}
+            <div class="flex flex-col gap-4 p-4">
+                {#each Array(5) as _, i}
+                    <div class="flex flex-col gap-2 p-4 border rounded-xl border-gray-200/50 bg-white/40">
+                        <div class="flex items-center justify-between mb-4">
+                            <Skeleton class="h-8 w-1/3" />
+                            <Skeleton class="h-8 w-8 rounded-full" />
+                        </div>
+                        <Skeleton class="h-32 w-full" />
+                    </div>
+                {/each}
+            </div>
+        {:else}
+            <VirtualList
+                {items}
+                {...rest}
+                onVisibleItemsChange={handleInternalVisibleChange}
+                onNearBottom={handleNearBottom}
+            >
+                {#snippet children(scope)}
+                    {@render children(scope)}
+                {/snippet}
+            </VirtualList>
+        {/if}
+    </div>
+{/key}

src/routes/Page.svelte

@@ -10,8 +10,8 @@ import ComparisonSlider from '$widgets/ComparisonSlider/ui/ComparisonSlider/Comp
 import { FontSearch } from '$widgets/FontSearch';
 import { SampleList } from '$widgets/SampleList';
 import CodeIcon from '@lucide/svelte/icons/code';
+import EyeIcon from '@lucide/svelte/icons/eye';
 import LineSquiggleIcon from '@lucide/svelte/icons/line-squiggle';
-import ScanEyeIcon from '@lucide/svelte/icons/scan-eye';
 import ScanSearchIcon from '@lucide/svelte/icons/search';
 import type { Snippet } from 'svelte';
 
@@ -59,7 +59,7 @@ function handleTitleStatusChanged(index: number, isPast: boolean, title?: Snippe
 
     <Section class="my-12 gap-8" index={1} onTitleStatusChange={handleTitleStatusChanged}>
         {#snippet icon({ className })}
-            <ScanEyeIcon class={className} />
+            <EyeIcon class={className} />
         {/snippet}
         {#snippet title({ className })}
             <h1 class={className}>

src/shared/shadcn/ui/spinner/index.ts

@@ -0,0 +1 @@
+export { default as Spinner } from './spinner.svelte';

src/shared/shadcn/ui/spinner/spinner.svelte

@@ -0,0 +1,14 @@
+<script lang="ts">
+import { cn } from '$shared/shadcn/utils/shadcn-utils.js';
+import Loader2Icon from '@lucide/svelte/icons/loader-2';
+import type { ComponentProps } from 'svelte';
+
+let { class: className, ...restProps }: ComponentProps<typeof Loader2Icon> = $props();
+</script>
+
+<Loader2Icon
+    role="status"
+    aria-label="Loading"
+    class={cn('size-4 animate-spin', className)}
+    {...restProps}
+/>

src/shared/ui/Loader/Loader.stories.svelte

@@ -0,0 +1,33 @@
+<script module>
+import { defineMeta } from '@storybook/addon-svelte-csf';
+import Loader from './Loader.svelte';
+
+const { Story } = defineMeta({
+    title: 'Shared/Loader',
+    tags: ['autodocs'],
+    parameters: {
+        docs: {
+            description: {
+                component: 'Spinner with optional message',
+            },
+            story: { inline: false }, // Render stories in iframe for state isolation
+        },
+    },
+    argTypes: {
+        message: {
+            control: 'text',
+            description: 'Optional message to display',
+            defaultValue: 'analyzing_data',
+        },
+        size: {
+            control: 'number',
+            description: 'Size of the spinner',
+            defaultValue: 20,
+        },
+    },
+});
+</script>
+
+<Story name="Default">
+    <Loader />
+</Story>

src/shared/ui/Loader/Loader.svelte

@@ -0,0 +1,77 @@
+<!--
+    Component: Loader
+    Displays a loading spinner with an optional message.
+-->
+<script lang="ts">
+import { fade } from 'svelte/transition';
+
+interface Props {
+    /**
+     * Icon size (in pixels)
+     * @default 20
+     */
+    size?: number;
+    /**
+     * Additional classes for container
+     */
+    class?: string;
+    /**
+     * Message text
+     * @default analyzing_data
+     */
+    message?: string;
+}
+
+let { size = 20, class: className = '', message = 'analyzing_data' }: Props = $props();
+</script>
+
+<div
+    class="absolute inset-x-0 inset-y-0 flex items-center justify-center gap-4 {className}"
+    in:fade={{ duration: 300 }}
+    out:fade={{ duration: 300 }}
+>
+    <div style:width="{size}px" style:height="{size}px">
+        <svg class="stroke-gray-900 stroke-1" viewBox="0 0 24 24" fill="none" xmlns="http://www.w3.org/2000/svg">
+            <g transform="translate(12, 12)">
+                <!-- Four corner brackets rotating -->
+                <g>
+                    <path
+                        d="M -8 -8 L -4 -8 M -8 -8 L -8 -4"
+                        stroke="currentColor"
+                        stroke-width="1"
+                        stroke-linecap="round"
+                    />
+                    <path
+                        d="M 8 -8 L 4 -8 M 8 -8 L 8 -4"
+                        stroke="currentColor"
+                        stroke-width="1"
+                        stroke-linecap="round"
+                    />
+                    <path
+                        d="M -8 8 L -4 8 M -8 8 L -8 4"
+                        stroke="currentColor"
+                        stroke-width="1"
+                        stroke-linecap="round"
+                    />
+                    <path d="M 8 8 L 4 8 M 8 8 L 8 4" stroke="currentColor" stroke-width="1" stroke-linecap="round" />
+
+                    <animateTransform
+                        attributeName="transform"
+                        type="rotate"
+                        from="0"
+                        to="360"
+                        dur="3s"
+                        repeatCount="indefinite"
+                    />
+                </g>
+            </g>
+        </svg>
+    </div>
+    <!-- Divider -->
+    <div class="w-px h-3 bg-gray-400/50"></div>
+
+    <!-- Message -->
+    <span class="font-mono text-[10px] uppercase tracking-[0.2em] text-gray-600 font-medium">
+        {message}
+    </span>
+</div>

src/shared/ui/Skeleton/Skeleton.stories.svelte

@@ -0,0 +1,41 @@
+<script module>
+import { defineMeta } from '@storybook/addon-svelte-csf';
+import Skeleton from './Skeleton.svelte';
+
+const { Story } = defineMeta({
+    title: 'Shared/Skeleton',
+    tags: ['autodocs'],
+    parameters: {
+        docs: {
+            description: {
+                component:
+                    'Skeleton component for loading states. Displays a shimmer animation when `animate` prop is true.',
+            },
+            story: { inline: false }, // Render stories in iframe for state isolation
+        },
+    },
+    argTypes: {
+        animate: {
+            control: 'boolean',
+            description: 'Whether to show the shimmer animation',
+        },
+    },
+});
+</script>
+
+<Story
+    name="Default"
+    args={{
+        animate: true,
+    }}
+>
+    <div class="flex flex-col gap-4 p-4 w-full">
+        <div class="flex flex-col gap-2 p-4 border rounded-xl border-gray-200/50 bg-white/40">
+            <div class="flex items-center justify-between mb-4">
+                <Skeleton class="h-8 w-1/3" />
+                <Skeleton class="h-8 w-8 rounded-full" />
+            </div>
+            <Skeleton class="h-32 w-full" />
+        </div>
+    </div>
+</Story>

src/shared/ui/Skeleton/Skeleton.svelte

@@ -0,0 +1,27 @@
+<!--
+    Component: Skeleton
+    Generic loading placeholder with shimmer animation.
+-->
+<script lang="ts">
+import { cn } from '$shared/shadcn/utils/shadcn-utils';
+import type { HTMLAttributes } from 'svelte/elements';
+
+interface Props extends HTMLAttributes<HTMLDivElement> {
+    /**
+     * Whether to show the shimmer animation
+     */
+    animate?: boolean;
+}
+
+let { class: className, animate = true, ...rest }: Props = $props();
+</script>
+
+<div
+    class={cn(
+        'rounded-md bg-gray-100/50 backdrop-blur-sm',
+        animate && 'animate-pulse',
+        className,
+    )}
+    {...rest}
+>
+</div>

src/shared/ui/VirtualList/VirtualList.svelte

@@ -101,13 +101,25 @@ interface Props {
      * @template T - The type of items in the list
      */
     children: Snippet<
-        [{ item: T; index: number; isFullyVisible: boolean; isPartiallyVisible: boolean; proximity: number }]
+        [
+            {
+                item: T;
+                index: number;
+                isFullyVisible: boolean;
+                isPartiallyVisible: boolean;
+                proximity: number;
+            },
+        ]
     >;
     /**
      * Whether to use the window as the scroll container.
      * @default false
      */
     useWindowScroll?: boolean;
+    /**
+     * Flag to show loading state
+     */
+    isLoading?: boolean;
 }
 
 let {
@@ -120,6 +132,7 @@ let {
     onNearBottom,
     children,
     useWindowScroll = false,
+    isLoading = false,
 }: Props = $props();
 
 // Reference to the ScrollArea viewport element for attaching the virtualizer

src/shared/ui/index.ts

@@ -1,27 +1,12 @@
-/**
- * Shared UI components exports
- *
- * Exports all shared UI components and their types
- */
-
-import CheckboxFilter from './CheckboxFilter/CheckboxFilter.svelte';
-import ComboControl from './ComboControl/ComboControl.svelte';
-import ComboControlV2 from './ComboControlV2/ComboControlV2.svelte';
-import ContentEditable from './ContentEditable/ContentEditable.svelte';
-import ExpandableWrapper from './ExpandableWrapper/ExpandableWrapper.svelte';
-import IconButton from './IconButton/IconButton.svelte';
-import SearchBar from './SearchBar/SearchBar.svelte';
-import Section from './Section/Section.svelte';
-import VirtualList from './VirtualList/VirtualList.svelte';
-
-export {
-    CheckboxFilter,
-    ComboControl,
-    ComboControlV2,
-    ContentEditable,
-    ExpandableWrapper,
-    IconButton,
-    SearchBar,
-    Section,
-    VirtualList,
-};
+export { default as CheckboxFilter } from './CheckboxFilter/CheckboxFilter.svelte';
+export { default as ComboControl } from './ComboControl/ComboControl.svelte';
+// ComboControlV2 might vary, assuming pattern holds or I'll fix later if build fails
+export { default as ComboControlV2 } from './ComboControlV2/ComboControlV2.svelte';
+export { default as ContentEditable } from './ContentEditable/ContentEditable.svelte';
+export { default as ExpandableWrapper } from './ExpandableWrapper/ExpandableWrapper.svelte';
+export { default as IconButton } from './IconButton/IconButton.svelte';
+export { default as Loader } from './Loader/Loader.svelte';
+export { default as SearchBar } from './SearchBar/SearchBar.svelte';
+export { default as Section } from './Section/Section.svelte';
+export { default as Skeleton } from './Skeleton/Skeleton.svelte';
+export { default as VirtualList } from './VirtualList/VirtualList.svelte';

src/widgets/ComparisonSlider/model/stores/comparisonStore.svelte.ts

@@ -136,6 +136,10 @@ class ComparisonStore {
         return !!this.#fontA && !!this.#fontB;
     }
 
+    get isLoading() {
+        return this.#isRestoring;
+    }
+
     /**
      * Public initializer (optional, as constructor starts it)
      * Kept for compatibility if manual re-init is needed

src/widgets/ComparisonSlider/ui/ComparisonSlider/ComparisonSlider.svelte

@@ -15,8 +15,10 @@ import {
     createTypographyControl,
 } from '$shared/lib';
 import type { LineData } from '$shared/lib';
+import { Loader } from '$shared/ui';
 import { comparisonStore } from '$widgets/ComparisonSlider/model';
 import { Spring } from 'svelte/motion';
+import { fade } from 'svelte/transition';
 import CharacterSlot from './components/CharacterSlot.svelte';
 import ControlsWrapper from './components/ControlsWrapper.svelte';
 import Labels from './components/Labels.svelte';
@@ -26,6 +28,8 @@ import SliderLine from './components/SliderLine.svelte';
 const fontA = $derived(comparisonStore.fontA);
 const fontB = $derived(comparisonStore.fontB);
 
+const isLoading = $derived(comparisonStore.isLoading || !comparisonStore.isReady);
+
 let container: HTMLElement | undefined = $state();
 let controlsWrapperElement = $state<HTMLDivElement | null>(null);
 let measureCanvas: HTMLCanvasElement | undefined = $state();
@@ -164,31 +168,33 @@ $effect(() => {
     </div>
 {/snippet}
 
-{#if fontA && fontB}
-    <!-- Hidden canvas used for text measurement by the helper -->
-    <canvas bind:this={measureCanvas} class="hidden" width="1" height="1"></canvas>
+<!-- Hidden canvas used for text measurement by the helper -->
+<canvas bind:this={measureCanvas} class="hidden" width="1" height="1"></canvas>
 
-    <div class="relative">
-        <div
-            bind:this={container}
-            role="slider"
-            tabindex="0"
-            aria-valuenow={Math.round(sliderPos)}
-            aria-label="Font comparison slider"
-            onpointerdown={startDragging}
-            class="
-                group relative w-full py-16 px-24 sm:py-24 sm:px-24 overflow-hidden
-                rounded-[2.5rem]
-                select-none touch-none cursor-ew-resize min-h-100 flex flex-col justify-center
-                backdrop-blur-lg bg-gradient-to-br from-gray-100/70 via-white/50 to-gray-100/60
-                border border-gray-300/40
-                shadow-[inset_0_4px_12px_0_rgba(0,0,0,0.12),inset_0_2px_4px_0_rgba(0,0,0,0.08),0_1px_2px_0_rgba(255,255,255,0.8)]
-                before:absolute before:inset-0 before:rounded-[2.5rem] before:p-[1px]
-                before:bg-gradient-to-br before:from-black/5 before:via-black/2 before:to-transparent
-                before:-z-10 before:blur-sm
-            "
-        >
-            <!-- Text Rendering Container -->
+<div class="relative">
+    <div
+        bind:this={container}
+        role="slider"
+        tabindex="0"
+        aria-valuenow={Math.round(sliderPos)}
+        aria-label="Font comparison slider"
+        onpointerdown={startDragging}
+        class="
+            group relative w-full py-16 px-24 sm:py-24 sm:px-24 overflow-hidden
+            rounded-[2.5rem]
+            select-none touch-none cursor-ew-resize min-h-100 flex flex-col justify-center
+            backdrop-blur-lg bg-gradient-to-br from-gray-100/70 via-white/50 to-gray-100/60
+            border border-gray-300/40
+            shadow-[inset_0_4px_12px_0_rgba(0,0,0,0.12),inset_0_2px_4px_0_rgba(0,0,0,0.08),0_1px_2px_0_rgba(255,255,255,0.8)]
+            before:absolute before:inset-0 before:rounded-[2.5rem] before:p-[1px]
+            before:bg-gradient-to-br before:from-black/5 before:via-black/2 before:to-transparent
+            before:-z-10 before:blur-sm
+        "
+    >
+        <!-- Text Rendering Container -->
+        {#if isLoading}
+            <Loader size={24} />
+        {:else}
             <div
                 class="
                     relative flex flex-col items-center gap-4
@@ -197,6 +203,8 @@ $effect(() => {
                     drop-shadow-[0_3px_6px_rgba(255,255,255,0.9)]
                 "
                 style:perspective="1000px"
+                in:fade={{ duration: 300, delay: 300 }}
+                out:fade={{ duration: 300 }}
             >
                 {#each charComparison.lines as line, lineIndex}
                     <div
@@ -212,8 +220,10 @@ $effect(() => {
             </div>
 
             <SliderLine {sliderPos} {isDragging} />
-        </div>
+        {/if}
+    </div>
 
+    {#if fontA && fontB && !isLoading}
         <Labels {fontA} {fontB} {sliderPos} weight={weightControl.value} />
         <!-- Since there're slider controls inside we put them outside the main one -->
         <ControlsWrapper
@@ -226,5 +236,5 @@ $effect(() => {
             {sizeControl}
             {heightControl}
         />
-    </div>
-{/if}
+    {/if}
+</div>

src/widgets/ComparisonSlider/ui/ComparisonSlider/components/ControlsWrapper.svelte

@@ -12,6 +12,7 @@ import { ComboControlV2 } from '$shared/ui';
 import { ExpandableWrapper } from '$shared/ui';
 import AArrowUP from '@lucide/svelte/icons/a-arrow-up';
 import { Spring } from 'svelte/motion';
+import { fade } from 'svelte/transition';
 
 interface Props {
     /**
@@ -121,6 +122,8 @@ $effect(() => {
         translateX({xSpring.current}px)
         rotateZ({rotateSpring.current}deg)
     "
+    in:fade={{ duration: 300, delay: 300 }}
+    out:fade={{ duration: 300, delay: 300 }}
 >
     <ExpandableWrapper
         bind:element={wrapper}

src/widgets/ComparisonSlider/ui/ComparisonSlider/components/Labels.svelte

@@ -17,6 +17,7 @@ import {
 } from '$shared/shadcn/ui/select';
 import { cn } from '$shared/shadcn/utils/shadcn-utils';
 import { comparisonStore } from '$widgets/ComparisonSlider/model';
+import { fade } from 'svelte/transition';
 
 interface Props<T> {
     /**
@@ -60,6 +61,8 @@ function selectFontB(font: UnifiedFont) {
     <div
         class="z-50 pointer-events-auto"
         onpointerdown={(e => e.stopPropagation())}
+        in:fade={{ duration: 300, delay: 300 }}
+        out:fade={{ duration: 300, delay: 300 }}
     >
         <SelectRoot type="single" disabled={!fontList.length}>
             <SelectTrigger

src/widgets/SampleList/ui/SampleList/SampleList.svelte

@@ -50,11 +50,9 @@ const displayRange = $derived.by(() => {
     const loadedCount = Math.min(offset + limit, total);
     return `Showing ${loadedCount} of ${total} fonts`;
 });
-</script>
 
-{#if unifiedFontStore.isFetching || unifiedFontStore.isLoading}
-    <span class="ml-2 text-xs text-muted-foreground/70">(Loading...)</span>
-{/if}
+const isLoading = $derived(unifiedFontStore.isFetching || unifiedFontStore.isLoading);
+</script>
 
 <FontVirtualList
     items={unifiedFontStore.fonts}
@@ -63,8 +61,15 @@ const displayRange = $derived.by(() => {
     itemHeight={280}
     useWindowScroll={true}
     weight={controlManager.weight}
+    {isLoading}
 >
-    {#snippet children({ item: font, isFullyVisible, isPartiallyVisible, proximity, index })}
+    {#snippet children({
+    item: font,
+    isFullyVisible,
+    isPartiallyVisible,
+    proximity,
+    index,
+})}
         <FontListItem {font} {isFullyVisible} {isPartiallyVisible} {proximity}>
             <FontSampler {font} bind:text {index} />
         </FontListItem>