A rough untested device time watching react native android module.

RNTimeWatcher.java

package io.invertase.firebase;

import android.app.Activity;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.content.BroadcastReceiver;

import com.facebook.react.bridge.Arguments;
import com.facebook.react.bridge.LifecycleEventListener;
import com.facebook.react.bridge.ReactApplicationContext;
import com.facebook.react.bridge.ReactContextBaseJavaModule;
import com.facebook.react.bridge.WritableMap;
import com.facebook.react.modules.core.DeviceEventManagerModule;


@SuppressWarnings("WeakerAccess")
public class RNTimeWatcher extends ReactContextBaseJavaModule implements LifecycleEventListener {
  private BroadcastReceiver broadcastReceiver;
  private static final String TAG = "RNTimeWatcher";


  public RNTimeWatcher(ReactApplicationContext reactContext) {
    super(reactContext);
    IntentFilter intentFilter = new IntentFilter();
    intentFilter.addAction(Intent.ACTION_TIME_TICK); // TODO not sure on this one
    intentFilter.addAction(Intent.ACTION_TIMEZONE_CHANGED);
    intentFilter.addAction(Intent.ACTION_TIME_CHANGED);
    broadcastReceiver = new BroadcastReceiver() {
      @Override
      public void onReceive(Context context, Intent intent) {
        final String action = intent.getAction();
        if (action.equals(Intent.ACTION_TIME_CHANGED) || action.equals(Intent.ACTION_TIMEZONE_CHANGED)) {
          if (getReactApplicationContext() != null) {
            WritableMap event = Arguments.createMap();
            
            if (action.equals(Intent.ACTION_TIME_CHANGED)) {
              event.putString("type", "time_changed");
            }

            if (action.equals(Intent.ACTION_TIMEZONE_CHANGED)) {
              event.putString("type", "timezone_changed");
            }
            
            
            getReactApplicationContext()
              .getJSModule(DeviceEventManagerModule.RCTDeviceEventEmitter.class)
              .emit("time_watcher", event);
          }
        }
      }
    };

    Activity activity = getCurrentActivity();
    if (activity != null) {
      getCurrentActivity().registerReceiver(broadcastReceiver, intentFilter);
    }
  }

  @Override
  public String getName() {
    return TAG;
  }

  @Override
  public void onHostResume() {
    // do nothing
  }

  @Override
  public void onHostPause() {
    // do nothing
  }

  @Override
  public void onHostDestroy() {
    Activity activity = getCurrentActivity();
    if (activity != null) {
      getCurrentActivity().unregisterReceiver(broadcastReceiver);
    }
  }
}