Slack Google Calendar for Team Events Replacement using Googgle App Scripts

appScript.js

// google configs
const calendarID = 'XXXXXXXX@import.calendar.google.com';
// slack configs
const webhookUrl = 'https://hooks.slack.com/services/XXXXXX/YYYYYYY/ZZZZZZ';
const channel = '#xxx'
const username = 'XXXXXX'

// note: this can be cleaned up but wanted to get something quick and dirty out there.
// throw this in a new App Script on https://script.google.com and have it trigger to run once a day.

function execute() {
  const cal = CalendarApp.getCalendarById(calendarID);

  let today = new Date();
  let tomorrow = new Date(today);
  tomorrow.setDate(tomorrow.getDate() + 1);
  let saturday = getNextSaturday(new Date(today));

  let todaysEvents = cal.getEventsForDay(today).map(cleanEvent);
  let upcomingEvents = cal.getEvents(tomorrow,saturday).map(cleanEvent);

  upcomingEvents = upcomingEvents.filter(upcomingEvent => !todaysEvents.some(todaysEvent => upcomingEvent.eventID === todaysEvent.eventID));
  
  // should only be called monday through friday
  if (today.getDay() < 6) {
    messageSlack(convertEventsToAttachments(todaysEvents), 1);
    messageSlack(convertEventsToAttachments(upcomingEvents), 0);
  }
}

function cleanEvent(event) {
  return {
    eventID: event.getId(),
    eventTitle: event.getTitle(),
    startDate: event.isAllDayEvent() ? event.getAllDayStartDate() : event.getStartTime(),
    endDate: event.isAllDayEvent() ? event.getAllDayEndDate() : event.getEndTime()
  };
}

function convertEventsToAttachments(events) {
  return events.map((event) => {
    if (event.startDate == event.endDate) {
      finalDateString = Utilities.formatDate(event.startDate, 'GMT-5','MMMMM d, yyyy');
    } else {
      finalDateString = Utilities.formatDate(event.startDate, 'GMT-5','MMMMM d - ') + Utilities.formatDate(new Date(event.endDate - 1), 'GMT-5','MMMMM d, yyyy');
    }
    return {
      'text': `*${event.eventTitle}*\r\n${finalDateString}`,
      'mrkdwn_in': ['text']
    };
  });
}

function getNextSaturday(today) {
  return new Date(today.setDate(today.getDate() + ((7 - today.getDay() + 6) % 7 || 7)));
}

function messageSlack(events, isToday) {
  let text = events.length == 0 ? `There are no events ${isToday ? 'today' : 'this week'}` : `There ${events.length > 1 ?  'are' : 'is'} *${events.length}* event${events.length > 1 ?  's' : ''} ${isToday ? 'today' : 'the rest of this week'}`;

  let payload = {
    'channel': channel,
    'username' : username,
    'icon_emoji' : ':calendar:',
    'text' : text,
    'attachments': events
  };
 
  let options = {
    'method': 'post',
    'contentType': 'application/json',
    'payload': JSON.stringify(payload)
  };
 
  return UrlFetchApp.fetch(webhookUrl, options);
}