WAYNEDEV

const makeTimes = (interval, elapsedTimeMin) => {
  const deltaTimeMin = Math.ceil(elapsedTimeMin / 30) * 30;
  const startTime = new Date(interval.start);
  const endTime = new Date(interval.end);
  if (startTime.getSeconds() > 0) {
    startTime.setSeconds(60);
  }
  startTime.setMinutes(Math.ceil(startTime.getMinutes() / 30) * 30);
  const result = [];
  while (startTime <= endTime) {
    result.push(startTime.toLocaleTimeString('ru-RU', { hour: '2-digit', minute: '2-digit' }));
    startTime.setMinutes(startTime.getMinutes() + deltaTimeMin);
  }
  return result;
}

makeTimes({start: 'Tue Aug 30 2022 09:00:00', end: 'Tue Aug 30 2022 16:30:00'}, 20);
// Array(16) [ "09:00", "09:30", "10:00", "10:30", "11:00", "11:30", "12:00", "12:30", "13:00", "13:30", … ]

makeTimes({start: 'Tue Aug 30 2022 09:00:00', end: 'Tue Aug 30 2022 16:30:00'}, 40);
// Array(8) [ "09:00", "10:00", "11:00", "12:00", "13:00", "14:00", "15:00", "16:00" ]

select 
	portfolio.id, portfolio.name,
	array_agg(json_build_object('src', photos.src, 'src_build', photos.src_build))
from portfolio
left join photos on portfolio.id = photos.portfolio_id
group by portfolio.id, portfolio.name
;