int getDefaults() {
        int defaults = options.optInt("androidDefaults");

        if (isAndroidChannelEnableVibration()) {
            defaults |= NotificationCompat.DEFAULT_VIBRATE;
        } else {
            defaults &= NotificationCompat.DEFAULT_VIBRATE;
        }

        if (getSound() == null) {
            defaults |= NotificationCompat.DEFAULT_SOUND;

            // No default sound
        } else {
            defaults &= NotificationCompat.DEFAULT_SOUND;
        }

        if (getLed() == null) {
            defaults |= NotificationCompat.DEFAULT_LIGHTS;

            // No default led
        } else {
            defaults &= NotificationCompat.DEFAULT_LIGHTS;
        }

        return defaults;
    }
Only for Android 7. Defaults for notification, which are bitwise or linked:
{@link NotificationCompat.DEFAULT_SOUND},
{@link NotificationCompat.DEFAULT_VIBRATE},
{@link NotificationCompat.DEFAULT_LIGHTS}.
src/android/Options.java