TypeError: Cannot read properties of null (reading 'toString') when trying to read

[ChristianNewton]

When trying to run the script, I get the following error:

TypeError: Cannot read properties of null (reading 'toString')
createEvent	@ Helpers.gs:503
processEvent	@ Helpers.gs:291
(anonymous)	@ Code.gs:220
startSync	@ Code.gs:219

I have tried it with other calendars and they don't have the same problem. I assume the error lies in the .ics file, so please let me know what you suggest. I unfortunately can not motify the file but if there is something I can modify in the script to fix the error, that would be great.

Here is a copy of my Code.gs file: https://pastebin.com/PkLL5ics. Thanks in advance!

[Lonestarjeepin]

Is this issue persistent every time this source calendar tries to run or does it run successfully the next time? I'm seeing this same error, but it's very sporadic so I haven't been able to troubleshoot it.

[ChristianNewton]

I had it running all day and it didn't sucessfully sync once. I tried with a few different source calendars and they worked immediately. I did try adding it to Google Calendar with the built-in option and it seemed to work fine.

[jonas0b1011001]

Seems like the failing event has an alarm without the 'trigger' property set, which is invalid syntax according the ical standard.

1. easy fix
   set var addAlerts = "no";

2. option
   change helpers.gs
   

   GAS-ICS-Sync/Helpers.gs

   Lines 502 to 513 in 71bb0a6

   	for (var valarm of valarms){
   	var trigger = valarm.getFirstPropertyValue('trigger').toString();
   	try{
   	var alarmTime = new ICAL.Time.fromString(trigger);
   	trigger = alarmTime.subtractDateTz(icalEvent.startDate).toString();
   	}catch(e){}
   	if (overrides.length < 5){ //Google supports max 5 reminder-overrides
   	var timer = parseNotificationTime(trigger);
   	if (0 <= timer && timer <= 40320)
   	overrides.push({'method' : 'popup', 'minutes' : timer});
   	}
   	}

   
   to

        for (var valarm of valarms){
          try{
            var trigger = valarm.getFirstPropertyValue('trigger').toString();
            var alarmTime = new ICAL.Time.fromString(trigger);
            trigger = alarmTime.subtractDateTz(icalEvent.startDate).toString();
            if (overrides.length < 5){ //Google supports max 5 reminder-overrides
              var timer = parseNotificationTime(trigger);
              if (0 <= timer && timer <= 40320)
                overrides.push({'method' : 'popup', 'minutes' : timer});
            }
          }catch(e){}
        }

This will still fail on said event but not crash the whole script.

[ChristianNewton]

Thanks man, those worked pretty well!