fix: add closePopup option for Chrome extension compatibility

[yogeshchoudhary147]

Fixes #1318

Problem

When using loginWithPopup() in Chrome extensions, the popup closes immediately after receiving the authorization response. This terminates the extension's service worker before token exchange completes, leaving the user unauthenticated.

Solution

Added a closePopup option to PopupConfigOptions:

• true (default): SDK closes the popup automatically after receiving the authorization response
• false: SDK does not close the popup. The caller is responsible for closing it, including on errors.

This gives users full control over the popup lifecycle, which is especially useful for Chrome extensions where closing too early terminates the service worker.

Changes

• utils.ts: Modified popup closing logic to respect closePopup option
• global.ts: Added JSDoc documentation for closePopup option with try/finally usage example
• loginWithPopup.test.ts: Added comprehensive test coverage for the closePopup option

Usage

const popup = window.open('', '_blank');
try {
  await auth0.loginWithPopup({}, {
    popup: popup,
    closePopup: false  // SDK won't close the popup
  });
  // Tokens are cached, authentication successful
} catch (error) {
  // Handle authentication errors
  console.error('Login failed:', error);
} finally {
  // Always close popup, even on errors
  popup.close();
}

This also provides flexibility for other use cases like showing post-login messages or executing additional logic before closing the popup.

Testing

Unit Tests

Added 4 test cases covering:

• Default behavior (popup closes immediately)
• Explicit closePopup: true
• closePopup: false (SDK does not close popup on success)
• closePopup: false (SDK does not close popup on token exchange failure)

All tests pass ✅

Manual Testing

Manually tested the fix in Chrome extension scenarios:

Before fix:

• ❌ Popup closes immediately after authorization
• ❌ Extension terminates before token exchange
• ❌ User remains unauthenticated (no tokens cached)

After fix with closePopup: false:

• ✅ SDK does not close the popup
• ✅ User closes popup in finally block after loginWithPopup completes
• ✅ Tokens are successfully cached before popup closes
• ✅ User is authenticated
• ✅ On reopening extension, user is logged in (tokens persisted in localStorage)
• ✅ Popup properly closed even when errors occur

Other scenarios:

• ✅ Default behavior: Popup closes immediately after authorization (no regression)

Backward Compatibility

No breaking changes. Default behavior unchanged - popup still closes immediately after authorization.

Credits

This PR builds upon the initial investigation and work by @ashwsn.

Closes #1318

[frederikprijck]

A boolean called closePopup to control when and not if a popup should be closed feels weird. I expect when setting it to false, it wouldnt close, so this code feels very unexpected:

if (config.closePopup === false && config.popup) {
  config.popup.close();
}