APG Patterns
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Slider

ユーザーが範囲内から値を選択できるインタラクティブなコントロール。

デモ

Volume
Progress
Rating
Vertical
Disabled

デモのみ表示 →

Native HTML

ネイティブ HTML を優先

このカスタムコンポーネントを使用する前に、ネイティブの<input type="range">要素の使用を検討してください。組み込みのキーボードサポート、JavaScriptなしでの動作、ネイティブのアクセシビリティサポートを提供します。


          <label for="volume">Volume</label>
<input type="range" id="volume" min="0" max="100" value="50">
        

ネイティブ要素では提供できないカスタムスタイリングが必要な場合、またはインタラクション中に特定の視覚的フィードバックが必要な場合にのみ、カスタム実装を使用してください。

ユースケース ネイティブ HTML カスタム実装
基本的な値の選択 推奨 不要
キーボードサポート 組み込み 手動実装
JavaScript無効時のサポート ネイティブで動作 フォールバック必要
フォーム統合 組み込み 手動実装
カスタムスタイリング 限定的(疑似要素) 完全な制御
ブラウザ間で一貫した外観 大きく異なる 一貫性あり
垂直方向 限定的なブラウザサポート 完全な制御

ネイティブの<input type="range">のスタイリングは、ブラウザ間で一貫性がないことで知られています。スタイリングにはベンダー固有の疑似要素(::-webkit-slider-thumb::-moz-range-thumbなど)が必要で、メンテナンスが複雑になる可能性があります。

アクセシビリティ

WAI-ARIA ロール

ロール 対象要素 説明
slider つまみ要素 ユーザーが範囲内から値を選択できるスライダーとして要素を識別します

slider ロールは、ユーザーがトラックに沿ってつまみを動かして値を選択するインタラクティブなコントロールに使用されます。 meter ロールとは異なり、スライダーはインタラクティブでキーボードフォーカスを受け取ります。

WAI-ARIA プロパティ

aria-valuenow (必須)

スライダーの現在の数値を示します。ユーザーが値を変更すると動的に更新されます。

Number
必須 はい
範囲 aria-valueminaria-valuemax の間である必要があります

aria-valuemin (必須)

スライダーの許容最小値を指定します。

Number
必須 はい
デフォルト 0

aria-valuemax (必須)

スライダーの許容最大値を指定します。

Number
必須 はい
デフォルト 100

aria-valuetext

現在の値の人間が読めるテキスト代替を提供します。数値だけでは十分な意味を伝えられない場合に使用します。

String
必須 いいえ(値にコンテキストが必要な場合は推奨)
"50%", "Medium", "3 of 5 stars"

aria-orientation

スライダーの向きを指定します。垂直スライダーの場合のみ "vertical" に設定します。水平の場合は省略します(デフォルト)。

"horizontal" | "vertical"
必須 いいえ
デフォルト horizontal(暗黙的)

aria-disabled

スライダーが無効でインタラクティブではないことを示します。

true | undefined
必須 いいえ

キーボードサポート

キー アクション
Right Arrow 値を1ステップ増加させる
Up Arrow 値を1ステップ増加させる
Left Arrow 値を1ステップ減少させる
Down Arrow 値を1ステップ減少させる
Home スライダーを最小値に設定する
End スライダーを最大値に設定する
Page Up 値を大きいステップで増加させる(デフォルト: step * 10)
Page Down 値を大きいステップで減少させる(デフォルト: step * 10)

アクセシブルな名前

スライダーはアクセシブルな名前を持つ必要があります。これは以下の方法で提供できます:

  • 表示されるラベル - label プロパティを使用して表示されるラベルを提供
  • aria-label - スライダーに見えないラベルを提供
  • aria-labelledby - 外部要素をラベルとして参照

ポインター操作

この実装はマウスとタッチ操作をサポートしています:

  • トラックをクリック - クリックした位置につまみを即座に移動
  • つまみをドラッグ - ドラッグ中の連続的な調整が可能
  • ポインターキャプチャ - ポインターがスライダーの外に出てもインタラクションを維持

ビジュアルデザイン

この実装は、アクセシブルなビジュアルデザインのためのWCAGガイドラインに従っています:

  • フォーカスインジケーター - つまみ要素に可視のフォーカスリング
  • 視覚的な塗りつぶし - 現在の値を比例的に表示
  • ホバー状態 - ホバー時の視覚的フィードバック
  • 無効状態 - スライダーが無効な時の明確な視覚的表示
  • 強制カラーモード - Windowsハイコントラストモードでのアクセシビリティのためにシステムカラーを使用

参考資料

ソースコード

Slider.svelte
<script lang="ts">
  interface SliderProps {
    defaultValue?: number;
    min?: number;
    max?: number;
    step?: number;
    largeStep?: number;
    orientation?: 'horizontal' | 'vertical';
    disabled?: boolean;
    showValue?: boolean;
    label?: string;
    valueText?: string;
    /** Format pattern for dynamic value display (e.g., "{value}%", "{value} of {max}") */
    format?: string;
    onvaluechange?: (value: number) => void;
    [key: string]: unknown;
  }

  let {
    defaultValue,
    min = 0,
    max = 100,
    step = 1,
    largeStep,
    orientation = 'horizontal',
    disabled = false,
    showValue = true,
    label,
    valueText,
    format,
    onvaluechange,
    ...restProps
  }: SliderProps = $props();

  // Utility functions
  function clamp(val: number, minVal: number, maxVal: number): number {
    return Math.min(maxVal, Math.max(minVal, val));
  }

  function roundToStep(val: number, stepVal: number, minVal: number): number {
    const steps = Math.round((val - minVal) / stepVal);
    const result = minVal + steps * stepVal;
    const decimalPlaces = (stepVal.toString().split('.')[1] || '').length;
    return Number(result.toFixed(decimalPlaces));
  }

  function getPercent(val: number, minVal: number, maxVal: number): number {
    if (maxVal === minVal) return 0;
    return ((val - minVal) / (maxVal - minVal)) * 100;
  }

  // Format value helper
  function formatValueText(
    val: number,
    formatStr: string | undefined,
    minVal: number,
    maxVal: number
  ): string {
    if (!formatStr) return String(val);
    return formatStr
      .replace('{value}', String(val))
      .replace('{min}', String(minVal))
      .replace('{max}', String(maxVal));
  }

  // Generate unique ID for label
  const labelId = `slider-label-${Math.random().toString(36).slice(2, 9)}`;

  // Refs
  let thumbEl: HTMLDivElement | null = null;
  let trackEl: HTMLDivElement | null = null;
  let isDragging = $state(false);

  // State - calculate initial value inline (warnings are acceptable for uncontrolled component)

  let value = $state(clamp(roundToStep(defaultValue ?? min, step, min), min, max));

  // Computed
  const isVertical = $derived(orientation === 'vertical');
  const effectiveLargeStep = $derived(largeStep ?? step * 10);
  const percent = $derived(getPercent(value, min, max));

  const ariaValueText = $derived(
    valueText ?? (format ? formatValueText(value, format, min, max) : undefined)
  );

  const displayText = $derived(valueText ? valueText : formatValueText(value, format, min, max));

  const ariaLabelledby = $derived(restProps['aria-labelledby'] ?? (label ? labelId : undefined));

  // Update value and dispatch event
  function updateValue(newValue: number) {
    const clampedValue = clamp(roundToStep(newValue, step, min), min, max);
    if (clampedValue !== value) {
      value = clampedValue;
      onvaluechange?.(clampedValue);
    }
  }

  // Calculate value from pointer position
  function getValueFromPointer(clientX: number, clientY: number): number {
    if (!trackEl) return value;

    const rect = trackEl.getBoundingClientRect();

    // Guard against zero-size track
    if (rect.width === 0 && rect.height === 0) {
      return value;
    }

    let pct: number;

    if (isVertical) {
      if (rect.height === 0) return value;
      pct = 1 - (clientY - rect.top) / rect.height;
    } else {
      if (rect.width === 0) return value;
      pct = (clientX - rect.left) / rect.width;
    }

    const rawValue = min + pct * (max - min);
    return clamp(roundToStep(rawValue, step, min), min, max);
  }

  // Keyboard handler
  function handleKeyDown(event: KeyboardEvent) {
    if (disabled) return;

    let newValue = value;

    switch (event.key) {
      case 'ArrowRight':
      case 'ArrowUp':
        newValue = value + step;
        break;
      case 'ArrowLeft':
      case 'ArrowDown':
        newValue = value - step;
        break;
      case 'Home':
        newValue = min;
        break;
      case 'End':
        newValue = max;
        break;
      case 'PageUp':
        newValue = value + effectiveLargeStep;
        break;
      case 'PageDown':
        newValue = value - effectiveLargeStep;
        break;
      default:
        return;
    }

    event.preventDefault();
    updateValue(newValue);
  }

  // Pointer handlers
  function handlePointerDown(event: PointerEvent) {
    if (disabled) return;

    event.preventDefault();
    if (!thumbEl) return;

    if (typeof thumbEl.setPointerCapture === 'function') {
      thumbEl.setPointerCapture(event.pointerId);
    }
    isDragging = true;
    thumbEl.focus();

    const newValue = getValueFromPointer(event.clientX, event.clientY);
    updateValue(newValue);
  }

  function handlePointerMove(event: PointerEvent) {
    if (!thumbEl) return;

    const hasCapture =
      typeof thumbEl.hasPointerCapture === 'function'
        ? thumbEl.hasPointerCapture(event.pointerId)
        : isDragging;

    if (!hasCapture) return;

    const newValue = getValueFromPointer(event.clientX, event.clientY);
    updateValue(newValue);
  }

  function handlePointerUp(event: PointerEvent) {
    if (thumbEl && typeof thumbEl.releasePointerCapture === 'function') {
      try {
        thumbEl.releasePointerCapture(event.pointerId);
      } catch {
        // Ignore
      }
    }
    isDragging = false;
  }

  // Track click handler
  function handleTrackClick(event: MouseEvent) {
    if (disabled) return;
    if (event.target === thumbEl) return;

    const newValue = getValueFromPointer(event.clientX, event.clientY);
    updateValue(newValue);
    thumbEl?.focus();
  }
</script>

<div
  class="apg-slider {isVertical ? 'apg-slider--vertical' : ''} {disabled
    ? 'apg-slider--disabled'
    : ''} {restProps.class || ''}"
>
  {#if label}
    <span id={labelId} class="apg-slider-label">
      {label}
    </span>
  {/if}
  <!-- svelte-ignore a11y_click_events_have_key_events a11y_no_static_element_interactions -->
  <div
    bind:this={trackEl}
    class="apg-slider-track"
    style="--slider-position: {percent}%"
    onclick={handleTrackClick}
  >
    <div class="apg-slider-fill" aria-hidden="true"></div>
    <div
      bind:this={thumbEl}
      role="slider"
      id={restProps.id}
      tabindex={disabled ? -1 : 0}
      aria-valuenow={value}
      aria-valuemin={min}
      aria-valuemax={max}
      aria-valuetext={ariaValueText}
      aria-label={restProps['aria-label']}
      aria-labelledby={ariaLabelledby}
      aria-orientation={isVertical ? 'vertical' : undefined}
      aria-disabled={disabled ? true : undefined}
      aria-describedby={restProps['aria-describedby']}
      data-testid={restProps['data-testid']}
      class="apg-slider-thumb"
      onkeydown={handleKeyDown}
      onpointerdown={handlePointerDown}
      onpointermove={handlePointerMove}
      onpointerup={handlePointerUp}
    ></div>
  </div>
  {#if showValue}
    <span class="apg-slider-value" aria-hidden="true">
      {displayText}
    </span>
  {/if}
</div>

使い方

使用例
<script>
  import Slider from './Slider.svelte';

  function handleChange(value) {
    console.log('Value changed:', value);
  }
</script>

<!-- Basic usage with aria-label -->
<Slider defaultValue={50} aria-label="Volume" />

<!-- With visible label -->
<Slider defaultValue={50} label="Volume" />

<!-- With format for display and aria-valuetext -->
<Slider
  defaultValue={75}
  label="Progress"
  format="{value}%"
/>

<!-- Custom range with step -->
<Slider
  defaultValue={3}
  min={1}
  max={5}
  step={1}
  label="Rating"
  format="{value} of {max}"
/>

<!-- Vertical slider -->
<Slider
  defaultValue={50}
  label="Volume"
  orientation="vertical"
/>

<!-- With callback -->
<Slider
  defaultValue={50}
  label="Value"
  onvaluechange={handleChange}
/>

API

プロパティ デフォルト 説明
defaultValue number min スライダーの初期値
min number 0 最小値
max number 100 最大値
step number 1 キーボードナビゲーションのステップ増分
largeStep number step * 10 PageUp/PageDown用の大きなステップ
orientation 'horizontal' | 'vertical' 'horizontal' スライダーの方向
disabled boolean false スライダーを無効にするかどうか
showValue boolean true 値のテキストを表示するかどうか
label string - 表示されるラベル(aria-labelledbyとしても使用)
valueText string - aria-valuetextの人間が読める値
format string - 表示およびaria-valuetextのフォーマットパターン(例: "{value}%", "{value} of {max}")
onvaluechange (value: number) => void - 値が変更されたときのコールバック

アクセシビリティのために、labelaria-label、または aria-labelledby のいずれかが必要です。

テスト

テストは、ARIA属性、キーボードインタラクション、ポインター操作、アクセシビリティ要件のAPG準拠を検証します。

テストカテゴリ

高優先度: ARIA 属性

テスト 説明
role="slider" 要素にsliderロールが設定されている
aria-valuenow 現在値が正しく設定・更新される
aria-valuemin 最小値が設定されている
aria-valuemax 最大値が設定されている
aria-valuetext 提供された場合、人間が読めるテキストが設定される
aria-disabled 無効状態が設定時に反映される

高優先度: アクセシブルな名前

テスト 説明
aria-label aria-label属性経由のアクセシブルな名前
aria-labelledby 外部要素参照経由のアクセシブルな名前
visible label 表示ラベルがアクセシブルな名前を提供

高優先度: キーボードインタラクション

テスト 説明
Arrow Right/Up 値を1ステップ増加
Arrow Left/Down 値を1ステップ減少
Home 値を最小値に設定
End 値を最大値に設定
Page Up/Down 値を大きいステップで増加/減少
Boundary clamping 値がmin/max制限を超えない
Disabled state 無効時はキーボード操作が無効

高優先度: フォーカス管理

テスト 説明
tabindex="0" つまみがフォーカス可能
tabindex="-1" 無効時はつまみがフォーカス不可

高優先度: 向き

テスト 説明
horizontal 水平スライダーにはaria-orientationなし
vertical aria-orientation="vertical"が設定される

中優先度: アクセシビリティ

テスト 説明
axe violations axe-coreによるアクセシビリティ違反なし

中優先度: エッジケース

テスト 説明
decimal values 小数ステップ値を正しく処理
negative range 負のmin/max範囲を処理
clamp to min min未満のdefaultValueはminにクランプ
clamp to max max超過のdefaultValueはmaxにクランプ

中優先度: コールバック

テスト 説明
onValueChange 変更時に新しい値でコールバックが呼ばれる

低優先度: HTML属性継承

テスト 説明
className カスタムクラスがコンテナに適用される
id ID属性が正しく設定される
data-* データ属性が引き継がれる

低優先度: フレームワーク間の一貫性

テスト 説明
All frameworks render sliders React、Vue、Svelte、Astroすべてがスライダー要素をレンダリング
Consistent ARIA attributes すべてのフレームワークで一貫したaria-valuenow、aria-valuemin、aria-valuemax
Keyboard navigation すべてのフレームワークが矢印キー、Home、Endキーボードナビゲーションをサポート

テストコード例

以下は実際のE2Eテストファイル(e2e/slider.spec.ts)です。

e2e/slider.spec.ts
import { test, expect } from '@playwright/test';
import AxeBuilder from '@axe-core/playwright';

/**
 * E2E Tests for Slider Pattern
 *
 * An interactive control that allows users to select a value from within a range.
 * Uses role="slider" with aria-valuenow, aria-valuemin, and aria-valuemax.
 *
 * APG Reference: https://www.w3.org/WAI/ARIA/apg/patterns/slider/
 */

const frameworks = ['react', 'vue', 'svelte', 'astro'] as const;

// ============================================
// Helper Functions
// ============================================

const getSlider = (page: import('@playwright/test').Page) => {
  return page.getByRole('slider');
};

const getSliderByLabel = (page: import('@playwright/test').Page, label: string) => {
  return page.getByRole('slider', { name: label });
};

// ============================================
// Framework-specific Tests
// ============================================

for (const framework of frameworks) {
  test.describe(`Slider (${framework})`, () => {
    test.beforeEach(async ({ page }) => {
      await page.goto(`patterns/slider/${framework}/demo/`);
      await getSlider(page).first().waitFor();

      // Wait for hydration - slider should have aria-valuenow
      const firstSlider = getSlider(page).first();
      await expect
        .poll(async () => {
          const valuenow = await firstSlider.getAttribute('aria-valuenow');
          return valuenow !== null;
        })
        .toBe(true);
    });

    // ------------------------------------------
    // 🔴 High Priority: APG ARIA Structure
    // ------------------------------------------
    test.describe('APG: ARIA Structure', () => {
      test('slider has role="slider"', async ({ page }) => {
        const slider = getSlider(page).first();
        await expect(slider).toHaveRole('slider');
      });

      test('slider has aria-valuenow', async ({ page }) => {
        const slider = getSliderByLabel(page, 'Volume');
        const valuenow = await slider.getAttribute('aria-valuenow');
        expect(valuenow).toBe('50');
      });

      test('slider has aria-valuemin', async ({ page }) => {
        const slider = getSliderByLabel(page, 'Volume');
        const valuemin = await slider.getAttribute('aria-valuemin');
        expect(valuemin).toBe('0');
      });

      test('slider has aria-valuemax', async ({ page }) => {
        const slider = getSliderByLabel(page, 'Volume');
        const valuemax = await slider.getAttribute('aria-valuemax');
        expect(valuemax).toBe('100');
      });

      test('slider with custom range has correct min/max', async ({ page }) => {
        const slider = getSliderByLabel(page, 'Rating');
        await expect(slider).toHaveAttribute('aria-valuemin', '1');
        await expect(slider).toHaveAttribute('aria-valuemax', '5');
        await expect(slider).toHaveAttribute('aria-valuenow', '3');
      });

      test('slider has accessible name via label', async ({ page }) => {
        const slider = getSliderByLabel(page, 'Volume');
        await expect(slider).toBeVisible();
      });

      test('slider has aria-valuetext when format is provided', async ({ page }) => {
        const slider = getSliderByLabel(page, 'Volume');
        await expect(slider).toHaveAttribute('aria-valuetext', '50%');
      });

      test('rating slider has descriptive aria-valuetext', async ({ page }) => {
        const slider = getSliderByLabel(page, 'Rating');
        await expect(slider).toHaveAttribute('aria-valuetext', '3 of 5');
      });

      test('vertical slider has aria-orientation="vertical"', async ({ page }) => {
        const slider = getSliderByLabel(page, 'Vertical');
        await expect(slider).toHaveAttribute('aria-orientation', 'vertical');
      });

      test('disabled slider has aria-disabled="true"', async ({ page }) => {
        const slider = getSliderByLabel(page, 'Disabled');
        await expect(slider).toHaveAttribute('aria-disabled', 'true');
      });
    });

    // ------------------------------------------
    // 🔴 High Priority: Keyboard Interaction
    // ------------------------------------------
    test.describe('APG: Keyboard Interaction', () => {
      test('ArrowRight increases value by step', async ({ page }) => {
        const slider = getSliderByLabel(page, 'Volume');
        await slider.click();
        await expect(slider).toBeFocused();

        const initialValue = await slider.getAttribute('aria-valuenow');
        await slider.press('ArrowRight');

        const newValue = await slider.getAttribute('aria-valuenow');
        expect(Number(newValue)).toBe(Number(initialValue) + 1);
      });

      test('ArrowLeft decreases value by step', async ({ page }) => {
        const slider = getSliderByLabel(page, 'Volume');
        await slider.click();
        await expect(slider).toBeFocused();

        const initialValue = await slider.getAttribute('aria-valuenow');
        await slider.press('ArrowLeft');

        const newValue = await slider.getAttribute('aria-valuenow');
        expect(Number(newValue)).toBe(Number(initialValue) - 1);
      });

      test('ArrowUp increases value by step', async ({ page }) => {
        const slider = getSliderByLabel(page, 'Volume');
        await slider.click();
        await expect(slider).toBeFocused();

        const initialValue = await slider.getAttribute('aria-valuenow');
        await slider.press('ArrowUp');

        const newValue = await slider.getAttribute('aria-valuenow');
        expect(Number(newValue)).toBe(Number(initialValue) + 1);
      });

      test('ArrowDown decreases value by step', async ({ page }) => {
        const slider = getSliderByLabel(page, 'Volume');
        await slider.click();
        await expect(slider).toBeFocused();

        const initialValue = await slider.getAttribute('aria-valuenow');
        await slider.press('ArrowDown');

        const newValue = await slider.getAttribute('aria-valuenow');
        expect(Number(newValue)).toBe(Number(initialValue) - 1);
      });

      test('Home sets value to minimum', async ({ page }) => {
        const slider = getSliderByLabel(page, 'Volume');
        await slider.click();
        await expect(slider).toBeFocused();

        await slider.press('Home');

        await expect(slider).toHaveAttribute('aria-valuenow', '0');
      });

      test('End sets value to maximum', async ({ page }) => {
        const slider = getSliderByLabel(page, 'Volume');
        await slider.click();
        await expect(slider).toBeFocused();

        await slider.press('End');

        await expect(slider).toHaveAttribute('aria-valuenow', '100');
      });

      test('PageUp increases value by large step', async ({ page }) => {
        const slider = getSliderByLabel(page, 'Volume');
        await slider.click();
        await expect(slider).toBeFocused();

        const initialValue = await slider.getAttribute('aria-valuenow');
        await slider.press('PageUp');

        const newValue = await slider.getAttribute('aria-valuenow');
        // Large step is typically step * 10 = 10
        expect(Number(newValue)).toBe(Number(initialValue) + 10);
      });

      test('PageDown decreases value by large step', async ({ page }) => {
        const slider = getSliderByLabel(page, 'Volume');
        await slider.click();
        await expect(slider).toBeFocused();

        const initialValue = await slider.getAttribute('aria-valuenow');
        await slider.press('PageDown');

        const newValue = await slider.getAttribute('aria-valuenow');
        // Large step is typically step * 10 = 10
        expect(Number(newValue)).toBe(Number(initialValue) - 10);
      });

      test('value does not exceed maximum', async ({ page }) => {
        const slider = getSliderByLabel(page, 'Volume');
        await slider.click();
        await expect(slider).toBeFocused();

        // Set to max first
        await slider.press('End');
        await expect(slider).toHaveAttribute('aria-valuenow', '100');

        // Try to go beyond max
        await slider.press('ArrowRight');
        await expect(slider).toHaveAttribute('aria-valuenow', '100');
      });

      test('value does not go below minimum', async ({ page }) => {
        const slider = getSliderByLabel(page, 'Volume');
        await slider.click();
        await expect(slider).toBeFocused();

        // Set to min first
        await slider.press('Home');
        await expect(slider).toHaveAttribute('aria-valuenow', '0');

        // Try to go below min
        await slider.press('ArrowLeft');
        await expect(slider).toHaveAttribute('aria-valuenow', '0');
      });

      test('Rating slider respects step of 1', async ({ page }) => {
        const slider = getSliderByLabel(page, 'Rating');
        await slider.click();
        await expect(slider).toBeFocused();

        // Initial value might change due to click position, so use Home first
        await slider.press('Home');
        await expect(slider).toHaveAttribute('aria-valuenow', '1');

        await slider.press('ArrowRight');
        await expect(slider).toHaveAttribute('aria-valuenow', '2');

        await slider.press('End');
        await expect(slider).toHaveAttribute('aria-valuenow', '5');

        // Should not exceed max
        await slider.press('ArrowRight');
        await expect(slider).toHaveAttribute('aria-valuenow', '5');
      });
    });

    // ------------------------------------------
    // 🔴 High Priority: Vertical Slider Keyboard
    // ------------------------------------------
    test.describe('APG: Vertical Slider Keyboard', () => {
      test('ArrowUp increases value in vertical slider', async ({ page }) => {
        const slider = getSliderByLabel(page, 'Vertical');
        await slider.click();
        await expect(slider).toBeFocused();

        const initialValue = await slider.getAttribute('aria-valuenow');
        await slider.press('ArrowUp');

        const newValue = await slider.getAttribute('aria-valuenow');
        expect(Number(newValue)).toBe(Number(initialValue) + 1);
      });

      test('ArrowDown decreases value in vertical slider', async ({ page }) => {
        const slider = getSliderByLabel(page, 'Vertical');
        await slider.click();
        await expect(slider).toBeFocused();

        const initialValue = await slider.getAttribute('aria-valuenow');
        await slider.press('ArrowDown');

        const newValue = await slider.getAttribute('aria-valuenow');
        expect(Number(newValue)).toBe(Number(initialValue) - 1);
      });
    });

    // ------------------------------------------
    // 🔴 High Priority: Focus Management
    // ------------------------------------------
    test.describe('APG: Focus Management', () => {
      test('slider is focusable', async ({ page }) => {
        const slider = getSliderByLabel(page, 'Volume');
        await slider.click();
        await expect(slider).toBeFocused();
      });

      test('slider has tabindex="0"', async ({ page }) => {
        const slider = getSliderByLabel(page, 'Volume');
        await expect(slider).toHaveAttribute('tabindex', '0');
      });

      test('disabled slider has tabindex="-1"', async ({ page }) => {
        const slider = getSliderByLabel(page, 'Disabled');
        await expect(slider).toHaveAttribute('tabindex', '-1');
      });
    });

    // ------------------------------------------
    // 🟡 Medium Priority: Disabled State
    // ------------------------------------------
    test.describe('Disabled State', () => {
      test('disabled slider does not change value on ArrowRight', async ({ page }) => {
        const slider = getSliderByLabel(page, 'Disabled');

        // Force focus via JavaScript (click won't work on disabled)
        await slider.evaluate((el) => (el as HTMLElement).focus());

        const initialValue = await slider.getAttribute('aria-valuenow');
        await page.keyboard.press('ArrowRight');

        const newValue = await slider.getAttribute('aria-valuenow');
        expect(newValue).toBe(initialValue);
      });

      test('disabled slider does not change value on Home', async ({ page }) => {
        const slider = getSliderByLabel(page, 'Disabled');

        // Force focus via JavaScript
        await slider.evaluate((el) => (el as HTMLElement).focus());

        await page.keyboard.press('Home');

        // Should still be 50 (default value)
        await expect(slider).toHaveAttribute('aria-valuenow', '50');
      });
    });

    // ------------------------------------------
    // 🟡 Medium Priority: aria-valuetext Updates
    // ------------------------------------------
    test.describe('aria-valuetext Updates', () => {
      test('aria-valuetext updates on value change', async ({ page }) => {
        const slider = getSliderByLabel(page, 'Volume');
        await slider.click();
        await expect(slider).toBeFocused();

        // Use Home to reset to known value
        await slider.press('Home');
        await expect(slider).toHaveAttribute('aria-valuetext', '0%');

        await slider.press('ArrowRight');
        await expect(slider).toHaveAttribute('aria-valuetext', '1%');
      });

      test('Rating slider aria-valuetext updates correctly', async ({ page }) => {
        const slider = getSliderByLabel(page, 'Rating');
        await slider.click();
        await expect(slider).toBeFocused();

        // Use Home to reset to known value (min=1)
        await slider.press('Home');
        await expect(slider).toHaveAttribute('aria-valuetext', '1 of 5');

        await slider.press('ArrowRight');
        await expect(slider).toHaveAttribute('aria-valuetext', '2 of 5');
      });
    });

    // ------------------------------------------
    // 🟢 Low Priority: Accessibility
    // ------------------------------------------
    test.describe('Accessibility', () => {
      test('has no axe-core violations', async ({ page }) => {
        const results = await new AxeBuilder({ page }).include('[role="slider"]').analyze();

        expect(results.violations).toEqual([]);
      });

      test('vertical slider has no axe-core violations', async ({ page }) => {
        const slider = getSliderByLabel(page, 'Vertical');
        await slider.scrollIntoViewIfNeeded();

        const results = await new AxeBuilder({ page })
          .include('[aria-orientation="vertical"]')
          .analyze();

        expect(results.violations).toEqual([]);
      });

      test('disabled slider has no axe-core violations', async ({ page }) => {
        const slider = getSliderByLabel(page, 'Disabled');
        await slider.scrollIntoViewIfNeeded();

        const results = await new AxeBuilder({ page }).include('[aria-disabled="true"]').analyze();

        expect(results.violations).toEqual([]);
      });
    });
  });
}

// ============================================
// Cross-framework Consistency Tests
// ============================================

test.describe('Slider - Cross-framework Consistency', () => {
  test('all frameworks render sliders', async ({ page }) => {
    for (const framework of frameworks) {
      await page.goto(`patterns/slider/${framework}/demo/`);
      await getSlider(page).first().waitFor();

      const sliders = getSlider(page);
      const count = await sliders.count();
      expect(count).toBeGreaterThanOrEqual(4); // Volume, Rating, Vertical, Disabled
    }
  });

  test('all frameworks have consistent ARIA attributes', async ({ page }) => {
    test.setTimeout(60000);

    for (const framework of frameworks) {
      await page.goto(`patterns/slider/${framework}/demo/`);
      await getSlider(page).first().waitFor();

      // Wait for hydration
      await expect
        .poll(async () => {
          const valuenow = await getSlider(page).first().getAttribute('aria-valuenow');
          return valuenow !== null;
        })
        .toBe(true);

      // Check Volume slider
      const volumeSlider = getSliderByLabel(page, 'Volume');
      await expect(volumeSlider).toHaveAttribute('aria-valuenow', '50');
      await expect(volumeSlider).toHaveAttribute('aria-valuemin', '0');
      await expect(volumeSlider).toHaveAttribute('aria-valuemax', '100');
      await expect(volumeSlider).toHaveAttribute('aria-valuetext', '50%');

      // Check Rating slider
      const ratingSlider = getSliderByLabel(page, 'Rating');
      await expect(ratingSlider).toHaveAttribute('aria-valuenow', '3');
      await expect(ratingSlider).toHaveAttribute('aria-valuemin', '1');
      await expect(ratingSlider).toHaveAttribute('aria-valuemax', '5');

      // Check Vertical slider
      const verticalSlider = getSliderByLabel(page, 'Vertical');
      await expect(verticalSlider).toHaveAttribute('aria-orientation', 'vertical');

      // Check Disabled slider
      const disabledSlider = getSliderByLabel(page, 'Disabled');
      await expect(disabledSlider).toHaveAttribute('aria-disabled', 'true');
    }
  });

  test('all frameworks support keyboard navigation', async ({ page }) => {
    test.setTimeout(60000);

    for (const framework of frameworks) {
      await page.goto(`patterns/slider/${framework}/demo/`);
      await getSlider(page).first().waitFor();

      // Wait for hydration
      await expect
        .poll(async () => {
          const valuenow = await getSlider(page).first().getAttribute('aria-valuenow');
          return valuenow !== null;
        })
        .toBe(true);

      const slider = getSliderByLabel(page, 'Volume');
      await slider.click();
      await expect(slider).toBeFocused();

      // Test Home (to reset to known value after click)
      await slider.press('Home');
      await expect(slider).toHaveAttribute('aria-valuenow', '0');

      // Test ArrowRight
      await slider.press('ArrowRight');
      await expect(slider).toHaveAttribute('aria-valuenow', '1');

      // Test End
      await slider.press('End');
      await expect(slider).toHaveAttribute('aria-valuenow', '100');
    }
  });
});

テストの実行

# Run unit tests for Slider
npm run test -- slider

# Run E2E tests for Slider (all frameworks)
npm run test:e2e:pattern --pattern=slider

# Run E2E tests for specific framework
npm run test:e2e:react:pattern --pattern=slider
npm run test:e2e:vue:pattern --pattern=slider
npm run test:e2e:svelte:pattern --pattern=slider
npm run test:e2e:astro:pattern --pattern=slider

テストツール

Slider.test.svelte.ts
import { render, screen } from '@testing-library/svelte';
import userEvent from '@testing-library/user-event';
import { axe } from 'jest-axe';
import { describe, expect, it, vi } from 'vitest';
import Slider from './Slider.svelte';
import SliderWithLabel from './SliderWithLabel.test.svelte';

describe('Slider (Svelte)', () => {
  // 🔴 High Priority: ARIA Attributes
  describe('ARIA Attributes', () => {
    it('has role="slider"', () => {
      render(Slider, {
        props: { 'aria-label': 'Volume' },
      });
      expect(screen.getByRole('slider')).toBeInTheDocument();
    });

    it('has aria-valuenow set to current value', () => {
      render(Slider, {
        props: { defaultValue: 50, 'aria-label': 'Volume' },
      });
      const slider = screen.getByRole('slider');
      expect(slider).toHaveAttribute('aria-valuenow', '50');
    });

    it('has aria-valuenow set to min when no defaultValue', () => {
      render(Slider, {
        props: { min: 10, 'aria-label': 'Volume' },
      });
      const slider = screen.getByRole('slider');
      expect(slider).toHaveAttribute('aria-valuenow', '10');
    });

    it('has aria-valuemin set (default: 0)', () => {
      render(Slider, {
        props: { 'aria-label': 'Volume' },
      });
      const slider = screen.getByRole('slider');
      expect(slider).toHaveAttribute('aria-valuemin', '0');
    });

    it('has aria-valuemax set (default: 100)', () => {
      render(Slider, {
        props: { 'aria-label': 'Volume' },
      });
      const slider = screen.getByRole('slider');
      expect(slider).toHaveAttribute('aria-valuemax', '100');
    });

    it('has custom aria-valuemin when provided', () => {
      render(Slider, {
        props: { defaultValue: 50, min: 10, 'aria-label': 'Volume' },
      });
      const slider = screen.getByRole('slider');
      expect(slider).toHaveAttribute('aria-valuemin', '10');
    });

    it('has custom aria-valuemax when provided', () => {
      render(Slider, {
        props: { defaultValue: 50, max: 200, 'aria-label': 'Volume' },
      });
      const slider = screen.getByRole('slider');
      expect(slider).toHaveAttribute('aria-valuemax', '200');
    });

    it('has aria-valuetext when valueText provided', () => {
      render(Slider, {
        props: { defaultValue: 75, valueText: '75 percent', 'aria-label': 'Volume' },
      });
      const slider = screen.getByRole('slider');
      expect(slider).toHaveAttribute('aria-valuetext', '75 percent');
    });

    it('does not have aria-valuetext when not provided', () => {
      render(Slider, {
        props: { defaultValue: 75, 'aria-label': 'Volume' },
      });
      const slider = screen.getByRole('slider');
      expect(slider).not.toHaveAttribute('aria-valuetext');
    });

    it('uses format for aria-valuetext', () => {
      render(Slider, {
        props: {
          defaultValue: 75,
          format: '{value}%',
          'aria-label': 'Volume',
        },
      });
      const slider = screen.getByRole('slider');
      expect(slider).toHaveAttribute('aria-valuetext', '75%');
    });

    it('has aria-disabled="true" when disabled', () => {
      render(Slider, {
        props: { disabled: true, 'aria-label': 'Volume' },
      });
      const slider = screen.getByRole('slider');
      expect(slider).toHaveAttribute('aria-disabled', 'true');
    });

    it('does not have aria-disabled when not disabled', () => {
      render(Slider, {
        props: { 'aria-label': 'Volume' },
      });
      const slider = screen.getByRole('slider');
      expect(slider).not.toHaveAttribute('aria-disabled');
    });
  });

  // 🔴 High Priority: Accessible Name
  describe('Accessible Name', () => {
    it('has accessible name via aria-label', () => {
      render(Slider, {
        props: { 'aria-label': 'Volume' },
      });
      expect(screen.getByRole('slider', { name: 'Volume' })).toBeInTheDocument();
    });

    it('has accessible name via aria-labelledby', () => {
      render(SliderWithLabel);
      expect(screen.getByRole('slider', { name: 'Brightness' })).toBeInTheDocument();
    });

    it('has accessible name via visible label', () => {
      render(Slider, {
        props: { label: 'Zoom Level' },
      });
      expect(screen.getByRole('slider', { name: 'Zoom Level' })).toBeInTheDocument();
    });
  });

  // 🔴 High Priority: Keyboard Interaction
  describe('Keyboard Interaction', () => {
    it('increases value by step on ArrowRight', async () => {
      const user = userEvent.setup();
      render(Slider, {
        props: { defaultValue: 50, step: 1, 'aria-label': 'Volume' },
      });
      const slider = screen.getByRole('slider');

      await user.click(slider);
      await user.keyboard('{ArrowRight}');

      expect(slider).toHaveAttribute('aria-valuenow', '51');
    });

    it('decreases value by step on ArrowLeft', async () => {
      const user = userEvent.setup();
      render(Slider, {
        props: { defaultValue: 50, step: 1, 'aria-label': 'Volume' },
      });
      const slider = screen.getByRole('slider');

      await user.click(slider);
      await user.keyboard('{ArrowLeft}');

      expect(slider).toHaveAttribute('aria-valuenow', '49');
    });

    it('sets min value on Home', async () => {
      const user = userEvent.setup();
      render(Slider, {
        props: { defaultValue: 50, min: 0, 'aria-label': 'Volume' },
      });
      const slider = screen.getByRole('slider');

      await user.click(slider);
      await user.keyboard('{Home}');

      expect(slider).toHaveAttribute('aria-valuenow', '0');
    });

    it('sets max value on End', async () => {
      const user = userEvent.setup();
      render(Slider, {
        props: { defaultValue: 50, max: 100, 'aria-label': 'Volume' },
      });
      const slider = screen.getByRole('slider');

      await user.click(slider);
      await user.keyboard('{End}');

      expect(slider).toHaveAttribute('aria-valuenow', '100');
    });

    it('increases value by large step on PageUp', async () => {
      const user = userEvent.setup();
      render(Slider, {
        props: { defaultValue: 50, step: 1, 'aria-label': 'Volume' },
      });
      const slider = screen.getByRole('slider');

      await user.click(slider);
      await user.keyboard('{PageUp}');

      expect(slider).toHaveAttribute('aria-valuenow', '60');
    });

    it('does not exceed max on ArrowRight', async () => {
      const user = userEvent.setup();
      render(Slider, {
        props: { defaultValue: 100, max: 100, 'aria-label': 'Volume' },
      });
      const slider = screen.getByRole('slider');

      await user.click(slider);
      await user.keyboard('{ArrowRight}');

      expect(slider).toHaveAttribute('aria-valuenow', '100');
    });

    it('does not change value when disabled', async () => {
      const user = userEvent.setup();
      render(Slider, {
        props: { defaultValue: 50, disabled: true, 'aria-label': 'Volume' },
      });
      const slider = screen.getByRole('slider');

      slider.focus();
      await user.keyboard('{ArrowRight}');

      expect(slider).toHaveAttribute('aria-valuenow', '50');
    });
  });

  // 🔴 High Priority: Focus Management
  describe('Focus Management', () => {
    it('has tabindex="0" on thumb', () => {
      render(Slider, {
        props: { 'aria-label': 'Volume' },
      });
      const slider = screen.getByRole('slider');
      expect(slider).toHaveAttribute('tabindex', '0');
    });

    it('has tabindex="-1" when disabled', () => {
      render(Slider, {
        props: { disabled: true, 'aria-label': 'Volume' },
      });
      const slider = screen.getByRole('slider');
      expect(slider).toHaveAttribute('tabindex', '-1');
    });
  });

  // 🔴 High Priority: Orientation
  describe('Orientation', () => {
    it('does not have aria-orientation for horizontal slider', () => {
      render(Slider, {
        props: { orientation: 'horizontal', 'aria-label': 'Volume' },
      });
      const slider = screen.getByRole('slider');
      expect(slider).not.toHaveAttribute('aria-orientation');
    });

    it('has aria-orientation="vertical" for vertical slider', () => {
      render(Slider, {
        props: { orientation: 'vertical', 'aria-label': 'Volume' },
      });
      const slider = screen.getByRole('slider');
      expect(slider).toHaveAttribute('aria-orientation', 'vertical');
    });
  });

  // 🟡 Medium Priority: Accessibility
  describe('Accessibility', () => {
    it('has no axe violations', async () => {
      const { container } = render(Slider, {
        props: { 'aria-label': 'Volume' },
      });
      const results = await axe(container);
      expect(results).toHaveNoViolations();
    });

    it('has no axe violations with visible label', async () => {
      const { container } = render(Slider, {
        props: { label: 'Volume' },
      });
      const results = await axe(container);
      expect(results).toHaveNoViolations();
    });

    it('has no axe violations when disabled', async () => {
      const { container } = render(Slider, {
        props: { disabled: true, 'aria-label': 'Volume' },
      });
      const results = await axe(container);
      expect(results).toHaveNoViolations();
    });

    it('has no axe violations for vertical slider', async () => {
      const { container } = render(Slider, {
        props: { orientation: 'vertical', 'aria-label': 'Volume' },
      });
      const results = await axe(container);
      expect(results).toHaveNoViolations();
    });
  });

  // 🟡 Medium Priority: Callbacks
  describe('Callbacks', () => {
    it('calls onvaluechange on keyboard interaction', async () => {
      const handleChange = vi.fn();
      const user = userEvent.setup();
      render(Slider, {
        props: { defaultValue: 50, onvaluechange: handleChange, 'aria-label': 'Volume' },
      });
      const slider = screen.getByRole('slider');

      await user.click(slider);
      await user.keyboard('{ArrowRight}');

      expect(handleChange).toHaveBeenCalledWith(51);
    });
  });

  // 🟡 Medium Priority: Edge Cases
  describe('Edge Cases', () => {
    it('handles decimal step values correctly', async () => {
      const user = userEvent.setup();
      render(Slider, {
        props: { defaultValue: 0.5, min: 0, max: 1, step: 0.1, 'aria-label': 'Volume' },
      });
      const slider = screen.getByRole('slider');

      await user.click(slider);
      await user.keyboard('{ArrowRight}');

      expect(slider).toHaveAttribute('aria-valuenow', '0.6');
    });

    it('handles negative min/max range', () => {
      render(Slider, {
        props: { defaultValue: 0, min: -50, max: 50, 'aria-label': 'Temperature' },
      });
      const slider = screen.getByRole('slider');
      expect(slider).toHaveAttribute('aria-valuenow', '0');
      expect(slider).toHaveAttribute('aria-valuemin', '-50');
      expect(slider).toHaveAttribute('aria-valuemax', '50');
    });

    it('clamps defaultValue to min', () => {
      render(Slider, {
        props: { defaultValue: -10, min: 0, max: 100, 'aria-label': 'Volume' },
      });
      const slider = screen.getByRole('slider');
      expect(slider).toHaveAttribute('aria-valuenow', '0');
    });

    it('clamps defaultValue to max', () => {
      render(Slider, {
        props: { defaultValue: 150, min: 0, max: 100, 'aria-label': 'Volume' },
      });
      const slider = screen.getByRole('slider');
      expect(slider).toHaveAttribute('aria-valuenow', '100');
    });
  });

  // 🟡 Medium Priority: Visual Display
  describe('Visual Display', () => {
    it('shows value when showValue is true (default)', () => {
      render(Slider, {
        props: { defaultValue: 75, 'aria-label': 'Volume' },
      });
      expect(screen.getByText('75')).toBeInTheDocument();
    });

    it('hides value when showValue is false', () => {
      render(Slider, {
        props: { defaultValue: 75, showValue: false, 'aria-label': 'Volume' },
      });
      expect(screen.queryByText('75')).not.toBeInTheDocument();
    });

    it('displays formatted value when format provided', () => {
      render(Slider, {
        props: {
          defaultValue: 75,
          format: '{value}%',
          'aria-label': 'Volume',
        },
      });
      expect(screen.getByText('75%')).toBeInTheDocument();
    });

    it('displays visible label when label provided', () => {
      render(Slider, {
        props: { label: 'Volume' },
      });
      expect(screen.getByText('Volume')).toBeInTheDocument();
    });
  });

  // 🟢 Low Priority: HTML Attribute Inheritance
  describe('HTML Attribute Inheritance', () => {
    it('applies class to container', () => {
      render(Slider, {
        props: { 'aria-label': 'Volume', class: 'custom-slider' },
      });
      const container = screen.getByRole('slider').closest('.apg-slider');
      expect(container).toHaveClass('custom-slider');
    });

    it('sets id attribute on slider element', () => {
      render(Slider, {
        props: { 'aria-label': 'Volume', id: 'my-slider' },
      });
      const slider = screen.getByRole('slider');
      expect(slider).toHaveAttribute('id', 'my-slider');
    });

    it('passes through data-* attributes', () => {
      render(Slider, {
        props: { 'aria-label': 'Volume', 'data-testid': 'custom-slider' },
      });
      expect(screen.getByTestId('custom-slider')).toBeInTheDocument();
    });
  });
});

リソース