feat: [#1864] Implement Cookie Store API

[TrevorBurnham]

Resolves #1864 and #1893

Summary

Implements the Cookie Store API, providing a modern, Promise-based interface for managing cookies. Full integration with the existing CookieContainer infrastructure — cookies set via cookieStore are visible via document.cookie and vice versa.

Changes

New Files

• packages/happy-dom/src/cookie-store/CookieStore.ts — Main implementation with get(), getAll(), set(), delete() methods
• packages/happy-dom/src/cookie-store/ICookieStoreGetOptions.ts — Options for get()/getAll()
• packages/happy-dom/src/cookie-store/ICookieStoreSetOptions.ts — Options for set()
• packages/happy-dom/src/cookie-store/ICookieStoreDeleteOptions.ts — Options for delete() (spec-correct subset: name, domain, path, partitioned only)
• packages/happy-dom/src/cookie-store/ICookieStoreItem.ts — Cookie item returned by get()/getAll()
• packages/happy-dom/src/event/events/CookieChangeEvent.ts — CookieChangeEvent with changed and deleted arrays
• packages/happy-dom/src/event/events/ICookieChangeEventInit.ts — Init interface for CookieChangeEvent
• packages/happy-dom/test/cookie-store/CookieStore.test.ts — Test suite (24 tests)

Modified Files

• packages/happy-dom/src/PropertySymbol.ts — Added cookieStore symbol
• packages/happy-dom/src/window/BrowserWindow.ts — Added CookieStore and CookieChangeEvent imports, properties, getters, and class exports
• packages/happy-dom/src/index.ts — Added exports for CookieStore, CookieChangeEvent, and all interfaces

API

// Get a single cookie by name
const cookie = await cookieStore.get('name');
const cookie = await cookieStore.get({ name: 'name' });

// Get all cookies (optionally filtered by name or URL)
const cookies = await cookieStore.getAll();
const cookies = await cookieStore.getAll('name');
const cookies = await cookieStore.getAll({ url: '/path' });

// Set a cookie
await cookieStore.set('name', 'value');
await cookieStore.set({
  name: 'name',
  value: 'value',
  expires: Date.now() + 86400000,
  path: '/',
  domain: 'example.com',
  sameSite: 'lax'
});

// Delete a cookie
await cookieStore.delete('name');
await cookieStore.delete({ name: 'name', path: '/' });

// Listen for changes
cookieStore.addEventListener('change', (event) => {
  console.log('Changed:', event.changed);
  console.log('Deleted:', event.deleted);
});

Spec Compliance

• [SecureContext]: secure flag is always set to true
• Default sameSite is 'strict' per spec
• value defaults to '' when omitted from the options object
• delete() accepts its own options type (ICookieStoreDeleteOptions) without value, expires, or sameSite
• getAll() with url option validates same-origin and throws SecurityError on cross-origin URLs
• expires accepts both number (Unix ms) and Date objects
• change event dispatches CookieChangeEvent with changed/deleted arrays on set() and delete()

Limitations

• change event only fires for mutations via CookieStore methods, not for cookies set via document.cookie (would require adding an observer mechanism to CookieContainer)

[Spixmaster]

Was this done an LLM? Who on earth writes such pull request descriptions?

[TrevorBurnham]

Yes, I used Claude Opus 4.5.

[Spixmaster]

Just out of interest, with https://github.com/copilot and Claude Opus 4.5 chosen?

[TrevorBurnham]

In this case I believe I used Kiro, the agentic IDE created by AWS (my employer). Outside of work, though, I mostly use Claude Code. I find GitHub Copilot very useful for answering questions about repos, but rarely use it to generate code.