Genarrative/src/hooks/useHostNavigationCanGoBack.ts

import { useEffect, useState } from 'react';

import {
  canUseNativeHostCapability,
  subscribeHostNavigationCanGoBack,
  subscribeHostRuntimeChange,
} from '../services/host-bridge/hostBridge';

function canUseHostNavigationCanGoBack() {
  return (
    canUseNativeHostCapability('host.events') &&
    canUseNativeHostCapability('navigation.canGoBack')
  );
}

export function useHostNavigationCanGoBack() {
  const [isSupported, setIsSupported] = useState(() =>
    canUseHostNavigationCanGoBack(),
  );
  const [canGoBack, setCanGoBack] = useState(false);

  useEffect(() => {
    let isDisposed = false;
    let unsubscribeNavigation: () => void = () => {};

    const syncSubscription = () => {
      unsubscribeNavigation();
      unsubscribeNavigation = () => {};

      const nextIsSupported = canUseHostNavigationCanGoBack();
      if (!isDisposed) {
        setIsSupported(nextIsSupported);
      }

      if (!nextIsSupported) {
        if (!isDisposed) {
          setCanGoBack(false);
        }
        return;
      }

      unsubscribeNavigation = subscribeHostNavigationCanGoBack((payload) => {
        if (!isDisposed) {
          setCanGoBack(payload.canGoBack);
        }
      });
    };

    syncSubscription();
    const unsubscribeRuntime = subscribeHostRuntimeChange(syncSubscription);

    return () => {
      isDisposed = true;
      unsubscribeRuntime();
      unsubscribeNavigation();
    };
  }, []);

  return {
    canGoBack,
    isSupported,
  };
}