Fixed issue

SlackIntegration.gs

function getURL(debug) {
  if(!debug)
    //#team-playmobile channel 
    return slack.inputHook.teamplaymobile;
  else {
    //#Me Slackbot 
    return slack.inputHook.sam;
  }
}

var tomorrow = new Date();
tomorrow.setDate(tomorrow.getDate() + 1);

function reportTomorrow() {
  var date = tomorrow;
  return getTeamMemberVacationStatus(date,1); 
}

function reportToday() {
  var date = new Date();
  return getTeamMemberVacationStatus(date,1); 
}

function getTeamMemberVacationStatus(date,forecast) {
  var members = fetchTeamMembersWithA1Notation();
  var dates = getDatesAndValuesOfVacationSheetWithA1Notation(date,forecast);
  var text = '';
  for(i = 0; i < dates.dates.length; i++) {
    var dateSheet =  dates.dates[i];
    var map = dates.mapping[dateSheet];
    dateEntries = '';
    for(j = 0; j < members.members.length; j++) {
      var member = members.members[j];
      var value = map.values[j]
      if(value) {
       dateEntries += '• _' + member + '_: *' + value + '*\n';  
      }
    }
    if(dateEntries != '' && forecast > 1) {
      text += Utilities.formatDate(dateSheet, "GMT+2", "E dd/MM/yyyy") + ':\n'+ dateEntries;
    } else if(dateEntries != '' && forecast === 1 && datesDaysEqual(date,new Date())) {
      text += 'Today:\n'+ dateEntries;
    } else if(dateEntries != '' && forecast === 1 && datesDaysEqual(tomorrow,date)) {
      text += 'Tomorrow:\n'+ dateEntries;
    }
  }
  return text;
}

function datesDaysEqual(date1,date2) {
  var date1String = Utilities.formatDate(date1, "GMT+2","dd/MM/yyyy")
  var date2String = Utilities.formatDate(date2, "GMT+2","dd/MM/yyyy")
 return  date1String == date2String;
}

function sendVacationReportForTomorrow() {  
  var url = getURL(false);
  var payload = {    
     "text" : reportTomorrow(),// <-- required parameter
     "mrkdwn": true,
  }
  sendToSlack_(url,payload)
}

function sendVacationReportForTodayAndTomorrow() {  
  var url = getURL(false);
  
  var today = reportToday();
  var tomorrow = reportTomorrow();
  if(today + tomorrow == '') {
    return;
  }
  var payload = {
     "text" : today+'\n'+tomorrow,
     "mrkdwn": true,
  }
  sendToSlack_(url,payload)
}


function sendToSlack_(url,payload) {
   var options =  {
    "method" : "post",
    "contentType" : "application/json",
    "payload" : JSON.stringify(payload)
  };
  return UrlFetchApp.fetch(url, options)
}


function getDatesAndValuesOfVacationSheetWithA1Notation(startDate,howManyDays) {
 var sheet = getVacationFirstSheet();
 var lastRow = sheet.getLastRow();
 var lastColumn = sheet.getLastColumn();
 var newDates = [];
 var mapping = {};
 for(i = 0; i < lastRow-3; i++) {
   range = sheet.getRange(3+i,1,1);
   if(!(range.getValue().getDate().valueOf() < startDate.getDate().valueOf())) {
     rangeValues = sheet.getRange(3+i,3,1,lastColumn-3);
     mapping[range.getValue()] = {'notation': range.getA1Notation().slice( 1 ),'values': rangeValues.getValues()[0]};
     newDates.push(range.getValue());
   }
   if(newDates.length >= howManyDays) {
     break;
   }
 }
  return {dates:newDates, mapping:mapping};
}

Vacation Sync.gs

function getSpreadsheet() {
  return SpreadsheetApp.openById(google.spreadsheet);
}

function getWhosOutCalendar() {
  return CalendarApp.getCalendarById(google.calendarWhosOut); 
}

function getVacationFirstSheet() {
  var ss = getSpreadsheet();
  var sheet = ss.getSheetByName('Vacations');
  return sheet;
}

function listAllCalendars() {
 var calendars = CalendarApp.getAllCalendars();
 for(i = 0; i < calendars.length; i++) {
   var calendar = calendars[i]
   Logger.log('Found %s with ID: %s',calendar.getName(),calendar.getId()) 
 } 
}
  
function updateVacationPlan() {
 var vacationsA1 = getA1NotationsOfVacations();
 var sheet = getVacationFirstSheet();
  for(i = 0; i < vacationsA1.length; i++) {
    var vac = vacationsA1[i];
    var cell = sheet.getRange(vac);
    if(cell.getValue() != 'Sick') {
      cell.setValue('Vacation');
    }
  }
}
  
function getA1NotationsOfVacations() {
  var dates = getDatesOfVacationSheetWithA1Notation();
  var members = fetchTeamMembersWithA1Notation();
  var A1NotVacations = [];
  for(i = 0; i < dates.dates.length; i++) {
    var date = dates.dates[i];
    var events = fetchCalendarEvents(date);
    var membersOnVacation = filterToRelevantTeamMembers(events,members.members);
    var rowMap = dates.mapping[date];
    for(j = 0; j < membersOnVacation.length; j++) {
      var member = membersOnVacation[j];
      var colMap = members.mapping[member];
      
      A1NotVacations.push(colMap+rowMap);
    }
  }
  return A1NotVacations;
}

function fetchCalendarEvents(date) {
 var returnEvents = []
 var calendar = getWhosOutCalendar()
  var events = calendar.getEventsForDay(date);
  for(j = 0; j < events.length; j++) {
    var event = events[j]
    returnEvents.push(event);
  }
  return returnEvents;
}
  
function getDatesOfVacationSheetWithA1Notation() {
 var sheet = getVacationFirstSheet();
 var lastRow = sheet.getLastRow();
 var lastColumn = sheet.getLastColumn();
 var newDates = [];
 var mapping = {};
 for(i = 0; i < lastRow-3; i++) {
   range = sheet.getRange(3+i,1,1);
   mapping[range.getValue()] = range.getA1Notation().slice( 1 );
   newDates.push(range.getValue());
 }
  return {dates:newDates, mapping:mapping};
}
  
function fetchTeamMembersWithA1Notation() {
  var sheet = getVacationFirstSheet();
  var lastColumn = sheet.getLastColumn();
  var range = sheet.getRange(2, 3,1,lastColumn-3);
  var members = range.getValues()[0];
  var mapping = {};
  for(i = 0; i < lastColumn-3; i++) {
    range = sheet.getRange(2,3+i,1,1);
    mapping[range.getValue()] = range.getA1Notation()[0];
  }
  return {members: members,mapping: mapping};
}

function filterToRelevantTeamMembers(events,members) {
 var membersHasEvent = [];
  for(e = 0; e < events.length; e++) {
    event = events[e];
    for(m = 0; m < members.length; m++) {
      member = members[m];
      var regex = new RegExp(member,'g');
      if(event.getTitle().match(regex)) {
        membersHasEvent.push(member)
      }
    }
  }
  return membersHasEvent;
}