fix(faq): scroll direct hash links

src/views/faq/__tests__/faq.test.tsx

@@ -0,0 +1,66 @@
+import * as React from 'react';
+import { createElement } from 'react';
+import { createRoot, type Root } from 'react-dom/client';
+import { MemoryRouter } from 'react-router-dom';
+import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest';
+import FAQ from '../faq';
+
+(globalThis as { IS_REACT_ACT_ENVIRONMENT?: boolean }).IS_REACT_ACT_ENVIRONMENT = true;
+const act = (React as { act?: (cb: () => void | Promise<void>) => void | Promise<void> }).act as (cb: () => void | Promise<void>) => void | Promise<void>;
+
+vi.mock('react-router-hash-link', () => ({
+  HashLink: ({ children, to }: { children: React.ReactNode; to: string }) => createElement('a', { href: to }, children),
+}));
+
+vi.mock('../../home/home', () => ({
+  Footer: () => createElement('div', { 'data-testid': 'footer' }, 'footer'),
+  HomeLogo: () => createElement('div', { 'data-testid': 'home-logo' }, 'home-logo'),
+}));
+
+let container: HTMLDivElement;
+let root: Root;
+let scrollIntoViewMock: ReturnType<typeof vi.fn>;
+
+const renderFAQ = async (initialEntry = '/faq') => {
+  await act(async () => {
+    root.render(createElement(MemoryRouter, { initialEntries: [initialEntry] }, createElement(FAQ)));
+  });
+};
+
+describe('FAQ', () => {
+  beforeEach(() => {
+    vi.clearAllMocks();
+    window.scrollTo = vi.fn();
+    scrollIntoViewMock = vi.fn();
+    Element.prototype.scrollIntoView = scrollIntoViewMock as unknown as typeof Element.prototype.scrollIntoView;
+    document.title = 'before';
+
+    container = document.createElement('div');
+    document.body.appendChild(container);
+    root = createRoot(container);
+  });
+
+  afterEach(() => {
+    act(() => root.unmount());
+    container.remove();
+  });
+
+  it('scrolls to the FAQ hash target on direct hash routes', async () => {
+    await renderFAQ('/faq#sage');
+
+    const sageQuestion = document.getElementById('sage');
+    expect(sageQuestion?.textContent).toBe('What is "sage"?');
+    expect(scrollIntoViewMock).toHaveBeenCalledTimes(1);
+    expect(scrollIntoViewMock.mock.contexts[0]).toBe(sageQuestion);
+    expect(window.scrollTo).not.toHaveBeenCalled();
+    expect(document.title).toBe('FAQ - 5chan');
+  });
+
+  it('scrolls to the top when there is no FAQ hash target', async () => {
+    await renderFAQ();
+
+    expect(scrollIntoViewMock).not.toHaveBeenCalled();
+    expect(window.scrollTo).toHaveBeenCalledWith(0, 0);
+    expect(document.title).toBe('FAQ - 5chan');
+  });
+});

src/views/faq/faq.tsx

@@ -1,5 +1,5 @@
 import { type ReactNode, useEffect } from 'react';
-import { Link } from 'react-router-dom';
+import { Link, useLocation } from 'react-router-dom';
 import { HashLink } from 'react-router-hash-link';
 import { Footer, HomeLogo } from '../home/home';
 import styles from './faq.module.css';
@@ -788,10 +788,20 @@ const FAQ_SECTIONS: FAQSection[] = [
 ];
 
 const FAQ = () => {
+  const { hash } = useLocation();
+
   useEffect(() => {
-    window.scrollTo(0, 0);
     document.title = 'FAQ - 5chan';
-  }, []);
+
+    const anchorId = hash.startsWith('#') ? hash.slice(1) : '';
+    const anchorElement = anchorId ? document.getElementById(anchorId) : null;
+    if (anchorElement) {
+      anchorElement.scrollIntoView();
+      return;
+    }
+
+    window.scrollTo(0, 0);
+  }, [hash]);
 
   return (
     <div className={styles.wrapper}>