Function getOrCreateSession

browse/src/cdp-inspector.ts:95–138

* Get or create a CDP session for the given page. * Enables DOM + CSS domains on first use.

(page: Page)

 * Enables DOM + CSS domains on first use.
 */
async function getOrCreateSession(page: Page): Promise<any> {
  let session = cdpSessions.get(page);
  if (session) {
    // Verify session is still alive
    try {
      await session.send('DOM.getDocument', { depth: 0 });
      return session;
    } catch (err: any) {
      // Session is stale — recreate (CDP disconnects throw on closed/Target errors)
      if (!err?.message?.includes('closed') && !err?.message?.includes('Target') && !err?.message?.includes('detached')) throw err;
      cdpSessions.delete(page);
      initializedPages.delete(page);
    }
  }

  session = await getOrCreateCdpSession(page, cdpSessions);

  // Enable DOM and CSS domains on first init for this page. The session
  // itself is cached + close-detached by getOrCreateCdpSession; the
  // initializedPages WeakSet is inspector-layer state that needs its
  // own close hook to stay in sync.
  if (!initializedPages.has(page)) {
    await session.send('DOM.enable');
    await session.send('CSS.enable');
    initializedPages.add(page);
    page.once('close', () => initializedPages.delete(page));
  }

  // Auto-detach on navigation — DOM/CSS domain state is tied to the
  // document. Close-detach (from getOrCreateCdpSession) handles the
  // tab-close case; framenavigated catches in-tab navigation that
  // invalidates inspector state without closing the tab.
  page.once('framenavigated', () => {
    try {
      session.detach().catch(() => {});
    } catch (err: any) {
      if (!err?.message?.includes('closed') && !err?.message?.includes('Target') && !err?.message?.includes('detached')) throw err;
    }
    cdpSessions.delete(page);
    initializedPages.delete(page);
  });

  return session;
}

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