Google Apps Script to automatically create, edit and delete events on work calendar for personal calendar events. Instructions on how to set up can be found at https://medium.com/@willroman/auto-block-time-on-your-work-google-calendar-for-your-personal-events-2a752ae91dab

block_personal_appts

function sync() {

  var id="XXXXXXXXX"; // CHANGE - id of the secondary calendar to pull events from

  var today=new Date();
  var enddate=new Date();
  enddate.setDate(today.getDate()+7); // how many days in advance to monitor and block off time
  today.setDate(today.getDate()-7); //how many days in the past to retroactivly update changes
  
  var secondaryCal=CalendarApp.getCalendarById(id);
  var secondaryEvents=secondaryCal.getEvents(today,enddate);
  
  var primaryCal=CalendarApp.getDefaultCalendar();
  var primaryEvents=primaryCal.getEvents(today,enddate); // all primary calendar events
  
  var primaryEventTitle="Booked"; // update this to the text you'd like to appear in the new events created in primary calendar
  
  var stat=1;
  var evi, existingEvent; 
  var primaryEventsFiltered = []; // to contain primary calendar events that were previously created from secondary calendar
  var primaryEventsUpdated = []; // to contain primary calendar events that were updated from secondary calendar
  var primaryEventsCreated = []; // to contain primary calendar events that were created from secondary calendar
  var primaryEventsDeleted = []; // to contain primary calendar events previously created that have been deleted from secondary calendar

  Logger.log('Number of primaryEvents: ' + primaryEvents.length);  
  Logger.log('Number of secondaryEvents: ' + secondaryEvents.length);
  
  // create filtered list of existing primary calendar events that were previously created from the secondary calendar
  for (pev in primaryEvents)
  {
    var pEvent = primaryEvents[pev];
    if (pEvent.getTitle() == primaryEventTitle)
    { primaryEventsFiltered.push(pEvent); }
  }
  
  // process all events in secondary calendar
  for (sev in secondaryEvents)
  {
    stat=1;
    evi=secondaryEvents[sev];
    
    // if the secondary event has already been blocked in the primary calendar, update it
    for (existingEvent in primaryEventsFiltered)
      {
        var pEvent = primaryEventsFiltered[existingEvent];
        var secondaryTitle = evi.getTitle();
        var secondaryDesc = evi.getDescription();
        if ((pEvent.getStartTime().getTime() == (evi.getStartTime().getTime() + 60000)) && (pEvent.getEndTime().getTime()==evi.getEndTime().getTime()))  //See below for the 1 minute adjustment
        {
          stat=0;
          ///pEvent.setTitle(primaryEventTitle);
          //pEvent.setDescription(secondaryTitle + '\n\n' + secondaryDesc);
          // event.setDescription(evi.getTitle() + '\n\n' + evi.getDescription());
          //pEvent.setVisibility(CalendarApp.Visibility.PRIVATE); // set blocked time as private appointments in work calendar
          ///primaryEventsUpdated.push(pEvent.getId());
          Logger.log('PRIMARY EVENT UPDATED'
                     + '\nprimaryId: ' + pEvent.getId() + ' \nprimaryTitle: ' + pEvent.getTitle() + ' \nprimaryDesc: ' + pEvent.getDescription());
        } 
      }

    if (stat==0) {
      Logger.log('Not creating new event for:' + evi.toString());
      continue;
    }
    
    var d = evi.getStartTime();
    var n = d.getDay();

    if (evi.isAllDayEvent() || (evi.getEndTime().getTime() - evi.getStartTime().getTime() > 86400000))
    {
      continue; // Do nothing if the event is an all-day or multi-day event. This script only syncs hour-based events
    }
    else if (n==1 || n==2 || n==3 || n==4 || n==5 || n==6 || n==7) // ~skip weekends. Delete this if you want to include weekends~
    // if the secondary event does not exist in the primary calendar, create it
    {
      var timeShift = new Date(evi.getStartTime().getTime() + 60000) //Adds one minute to start time so it displays properly
      var newEvent = primaryCal.createEvent(primaryEventTitle,timeShift,evi.getEndTime()); // change the Booked text to whatever you would like your merged event titles to be
      // alternative version below that copies the exact secondary event information into the primary calendar event
      // var newEvent = primaryCal.createEvent(evi.getTitle(),evi.getStartTime(),evi.getEndTime(), {location: evi.getLocation(), description: evi.getDescription()});  
      //newEvent.setDescription(evi.getTitle() + '\n\n' + evi.getDescription());
      //newEvent.setVisibility(CalendarApp.Visibility.PRIVATE); // set blocked time as private appointments in work calendar
      newEvent.removeAllReminders(); // so you don't get double notifications. Delete this if you want to keep the default reminders for your newly created primary calendar events
      primaryEventsCreated.push(newEvent.getId());
      Logger.log('PRIMARY EVENT CREATED'
                 + '\nprimaryId: ' + newEvent.getId() + '\nprimaryTitle: ' + newEvent.getTitle() + '\nprimaryDesc ' + newEvent.getDescription() + '\n');
    }
  }

  // if a primary event previously created no longer exists in the secondary calendar, delete it
  for (pev in primaryEventsFiltered)
  {
    var pevIsUpdatedIndex = primaryEventsUpdated.indexOf(primaryEventsFiltered[pev].getId());
    if (pevIsUpdatedIndex == -1)
    { 
      var pevIdToDelete = primaryEventsFiltered[pev].getId();
      Logger.log(pevIdToDelete + ' deleted');
      primaryEventsDeleted.push(pevIdToDelete);
      primaryEventsFiltered[pev].deleteEvent();
    }
  }  

  Logger.log('Primary events previously created: ' + primaryEventsFiltered.length);
  Logger.log('Primary events updated: ' + primaryEventsUpdated.length);
  Logger.log('Primary events deleted: ' + primaryEventsDeleted.length);
  Logger.log('Primary events created: ' + primaryEventsCreated.length);

}  

Hello - I tried your script instead of the one you originally forked from because I wanted to take advantage of some of the features like past events. However I am experiencing a couple issues:

1. The first time I run the script it works well, but then when it repeats it removes some of the events. The log shows multiple "deleted" events even if no changes occurred between runs.
2. Events that were created by Gmail (e.g. flights) do not seem to transfer over on yours even though they do on the original script.

Please let me know if you're able to resolve these and I'd be happy to try your script again. Thanks!