date-to-period.js

// @flow

export type TimePeriod = 'am' | 'pm';
export type TimeOfTheDay = { hour: number, minute: number, period: TimePeriod };
const getTimeOfTheDay = (date: Date): TimeOfTheDay => ({
  hour: date.getHours() > 12 ? date.getHours() - 12 : date.getHours(),
  minute: date.getMinutes(),
  period: date.getHours() >= 12 ? 'pm' : 'am',
});

const dateToPeriod = (startTime: Date, endTime: Date): string => {
  const time = [];
  const start = getTimeOfTheDay(startTime);
  const end = getTimeOfTheDay(endTime);
  time.push(`${start.hour}:${start.minute}`);
  time.push(`${end.hour}:${end.minute}${end.period}`);
  return time.join('-');
};

export default dateToPeriod;