Replicon iCalendar -> JSON Converter. Takes the iCal feed from Replicon and converts it into JSON as best it can. Deals with a bunch of edge cases. You can adapt this to your needs easily enough.

ical-to-json.js

var t = `BEGIN:VCALENDAR
PRODID:-//Replicon Inc.//dev//EN
CALSCALE: GREGORIAN
BEGIN:VEVENT
DTSTART;VALUE=DATE:20220118
DTEND;VALUE=DATE:20220122
TRANSP:OPAQUE
UID:urn:replicon-tenant:11111:time-off:35
DTSTAMP:20220131T133700Z
SUMMARY:Bereavement - Doe, Jane
DESCRIPTION:Start Date : Full Day, End Date : Full Day
PRIORITY:3
END:VEVENT
BEGIN:VEVENT
DTSTART;VALUE=DATE:20220204
DTEND;VALUE=DATE:20220205
TRANSP:OPAQUE
UID:urn:replicon-tenant:11111:time-off:51
DTSTAMP:20220131T162111Z
SUMMARY:Smith, John
DESCRIPTION:Full Day
PRIORITY:3
END:VEVENT
BEGIN:VEVENT
DTSTART:20220216T130000Z
DTEND:20220216T170000Z
TRANSP:OPAQUE
UID:urn:replicon-tenant:11111:time-off:531
DTSTAMP:20220217T142637Z
SUMMARY:Comp - Bloggs, Joe
DESCRIPTION:Half Day
PRIORITY:3
END:VEVENT
END:VCALENDAR`;

var inEventBlock = false;
var events = [];
var evt;
var match;

var lines = t.split('\n');
for (var i=0; i<lines.length; i++) {
    var line = lines[i];
    if (line=='BEGIN:VEVENT') {
        evt = {};
        inEventBlock = true;
    }
    
    if (line=='END:VEVENT') {
        events.push(evt);
        inEventBlock = false;
    }

    if (inEventBlock) {
        line = line.replace('DTSTART;VALUE=DATE:', 'DTSTART:');
        line = line.replace('DTEND;VALUE=DATE:', 'DTEND:');
        
        match = 'DTSTART:';
        if(line.indexOf(match)>-1) evt.start = line.replace(match, '');

        match = 'DTEND:';
        if(line.indexOf(match)>-1) evt.end = line.replace(match, '');
        
        match = 'SUMMARY:';
        if(line.indexOf(match)>-1) {
            var linesplit = line.replace(match, '').split(' - ');
            if (linesplit.length>1) {
                evt.type = linesplit[0];
                evt.user = linesplit[1];
            } else {
                evt.type = '';
                evt.user = linesplit[0];
            }
        }

        match = 'DESCRIPTION:';
        if(line.indexOf(match)>-1) {
            line = line.replace(match, '');
            linesplit = line.split(', ');
			if (linesplit.length>1) {
                evt.startf = linesplit[0].replace('Start Date : ', '');
                evt.endf = linesplit[1].replace('End Date : ', '');
            } else {
                evt.startf = line;
                evt.endf = line;
            }
        }
    }
}

console.log(events);

/* RESULTING OBJECT LOOKS LIKE THIS ...

[
    {
        "start": "20220118",
        "end": "20220122",
        "type": "Bereavement",
        "user": "Doe, Jane",
        "startf": "Full Day",
        "endf": "Full Day"
    },
    {
        "start": "20220204",
        "end": "20220205",
        "type": "",
        "user": "Smith, John",
        "startf": "Full Day",
        "endf": "Full Day"
    },
    {
        "start": "20220216T130000Z",
        "end": "20220216T170000Z",
        "type": "Comp",
        "user": "Bloggs, Joe",
        "startf": "Half Day",
        "endf": "Half Day"
    }
]

*/