Bridge/Symfony/Serializer/Normalizer/RelayPointNormalizer.php
protected function localizedDayOfWeek($dayOfWeek)
    {
        if (class_exists('\IntlDateFormatter')) {
            $date = new \DateTime('2017-01-01'); // Starts sunday
            $date->modify('+' . $dayOfWeek . ' days');

            $formatter = \IntlDateFormatter::create(
                $this->localeProvider->getCurrentLocale(),
                \IntlDateFormatter::NONE,
                \IntlDateFormatter::NONE,
                $date->getTimezone(),
                null,
                'eeee'
            );

            return $formatter->format($date->getTimestamp());
        }

        return [
                   1 => 'Monday',
                   2 => 'Tuesday',
                   3 => 'Wednesday',
                   4 => 'Thursday',
                   5 => 'Friday',
                   6 => 'Saturday',
                   7 => 'Sunday',
               ][$dayOfWeek];
    }
protected function localizedDayOfWeek($dayOfWeek)
    {
        if (class_exists('\IntlDateFormatter')) {
            $date = new \DateTime('2017-01-01'); // Starts sunday
            $date->modify('+' . $dayOfWeek . ' days');

            $formatter = \IntlDateFormatter::create(
                $this->localeProvider->getCurrentLocale(),
                \IntlDateFormatter::NONE,
                \IntlDateFormatter::NONE,
                $date->getTimezone(),
                null,
                'eeee'
            );

            return $formatter->format($date->getTimestamp());
        }

        return [
                   1 => 'Monday',
                   2 => 'Tuesday',
                   3 => 'Wednesday',
                   4 => 'Thursday',
                   5 => 'Friday',
                   6 => 'Saturday',
                   7 => 'Sunday',
               ][$dayOfWeek];
    }
Returns the localized day of week.

@param int $dayOfWeek

@return string