public function getSettings()
    {
        $settings = [];
        $map = [
            'localStrictModeEnabled' => 'strictMode',
            'localMonthsOverflow' => 'monthOverflow',
            'localYearsOverflow' => 'yearOverflow',
            'localHumanDiffOptions' => 'humanDiffOptions',
            'localToStringFormat' => 'toStringFormat',
            'localSerializer' => 'toJsonFormat',
            'localMacros' => 'macros',
            'localGenericMacros' => 'genericMacros',
            'locale' => 'locale',
            'tzName' => 'timezone',
            'localFormatFunction' => 'formatFunction',
        ];
        foreach ($map as $property => $key) {
            $value = $this->$property ?? null;
            if ($value !== null) {
                $settings[$key] = $value;
            }
        }

        return $settings;
    }