@bimetal/overlay-headless

Canonical, framework-agnostic overlay controller — the shared core for the overlay family (Dialog first; Popover / Tooltip / Menu / Drawer to follow). It owns the open/close state and the dismiss policy (whether an Esc or backdrop dismiss is honored); it is deliberately DOM-free. The render-layer bindings install the focus trap (@bimetal/a11y-dom), the scroll lock and the backdrop, and feed dismiss gestures back via requestClose(reason).

import { createOverlayController } from '@bimetal/overlay-headless';

const dialog = createOverlayController({ onOpenChange: (open) => {} });
dialog.open();
dialog.requestClose('esc');       // closes iff config.closeOnEsc
dialog.requestClose('backdrop');  // closes iff config.closeOnBackdrop
dialog.close();                   // force-close (a close button / app action)

• open() / close() / toggle() — drive the state (close() bypasses policy).
• requestClose('esc' | 'backdrop' | 'programmatic') — the single place the dismiss decision lives, so no binding diverges.
• getSnapshot() / subscribe() — identity-stable snapshot for useSyncExternalStore.

Part of the BIMETAL component family. Apache-2.0.