How to use the rrule.RRule.parseString function in rrule

id: profile.id,
            owner: profile.owner,
            name: profile.name,
            version: profile.version,
            title: profile.title,
            include: job.profiles.some(id => id === profile.id)
          }));
        });

        // schedule form
        const hasSchedule = job.recurrence.length > 0;
        scheduleGroup.get('name').setValue(job.name);
        scheduleGroup.get('include').setValue(hasSchedule);

        if (hasSchedule) {
          const rule = RRule.parseString(job.recurrence);
          const hasUntil = !!rule.until;
          const hasRepeat = !!rule.interval;
          const start = moment.utc(rule.dtstart);

          scheduleGroup.get('start.datetime').setValue({
            month: start.month(),
            date: start.date(),
            year: start.year(),
            hour: start.hour(),
            minute: start.minute()
          });

          if (hasUntil) {
            const end = moment.utc(rule.until);
            scheduleGroup.get('end.include').setValue(hasUntil);
            scheduleGroup.get('end.datetime').setValue({

delete data[k];

        // only events with summary are interesting
        if ((ev.summary !== undefined) && (ev.type === 'VEVENT')) {
            adapter.log.debug('ev:' + JSON.stringify(ev));
            if (!ev.end) {
                ev.end = ce.clone(ev.start);
                if (!ev.start.getHours() && !ev.start.getMinutes() && !ev.start.getSeconds()) {
                    ev.end.setDate(ev.end.getDate() + 1);
                }
            }
            // aha, it is RRULE in the event --> process it
            if (ev.rrule !== undefined) {
                const eventLength = ev.end.getTime() - ev.start.getTime();

                const options = RRule.parseString(ev.rrule.toString());
                // convert times temporary to UTC
                options.dtstart = addOffset(ev.start, -getTimezoneOffset(ev.start));
                if (options.until) {
                    options.until = addOffset(options.until, -getTimezoneOffset(options.until));
                }
                adapter.log.debug('options:' + JSON.stringify(options));

                const rule = new RRule(options);

                let now3 = new Date(now2.getTime() - eventLength);
                if (now2 < now3) {
                    now3 = now2;
                }
                adapter.log.debug('RRule event:' + ev.summary + '; start:' + ev.start.toString() + '; endpreview:' + endpreview.toString() + '; today:' + today + '; now2:' + now2 + '; now3:' + now3 + '; rule:' + JSON.stringify(rule));

                let dates = [];

IcalFile.prototype.getRrule = function(event)
{
    if (undefined === event.getProperty('RRULE')) {
        return null;
    }

    let RRule = require('rrule').RRule;

    let options = RRule.parseString(event.getProperty('RRULE').format()[0].substr(6));
    options.dtstart = event.getProperty('DTSTART').value;

    return new RRule(options);
};

function processRRule(ev, endpreview, today, realnow, node, config) {
        var eventLength = ev.end.getTime() - ev.start.getTime();

        var options = RRule.parseString(ev.rrule.toString());
        options.dtstart = addOffset(ev.start, -getTimezoneOffset(ev.start));
        if (options.until) {
            options.until = addOffset(options.until, -getTimezoneOffset(options.until));
        }
        node.debug('options:' + JSON.stringify(options));

        var rule = new RRule(options);
        var now2 = new Date();
        now2.setHours(0, 0, 0, 0);
        var now3 = new Date(now2.getTime() - eventLength);
        if (now2 < now3) now3 = now2;
        node.debug(
            'RRule event:' +
                ev.summary +
                '; start:' +
                ev.start.toString() +

function processRRule(ev, endpreview, today, realnow, node, config) {
        var eventLength = ev.end.getTime() - ev.start.getTime();
        var options = RRule.parseString(ev.rrule.toString());
        options.dtstart = addOffset(ev.start, -getTimezoneOffset(ev.start));
        if (options.until) {
            options.until = addOffset(options.until, -getTimezoneOffset(options.until));
        }
        node.debug('options:' + JSON.stringify(options));
        var rule = new RRule(options);
        var now2 = new Date();
        now2.setHours(0, 0, 0, 0);
        var now3 = new Date(now2.getTime() - eventLength);
        if (now2 < now3)
            now3 = now2;
        node.debug('RRule event:' +
            ev.summary +
            '; start:' +
            ev.start.toString() +
            '; endpreview:' +

const AccrualPeriodicityInput: FunctionComponent = props => {
    const recurrenceRuleOptions = props.accrualPeriodicityRecurrenceRule
        ? RRule.parseString(props.accrualPeriodicityRecurrenceRule)
        : DEFAULT_CUSTOM_INPUT_VALUE;

    const onWeekDayClick = (
        recurrenceRuleOptions: Partial,
        weekday: Weekday
    ) => {
        return () => {
            const selectedWeekDays: Weekday[] = Array.isArray(
                recurrenceRuleOptions.byweekday
            )
                ? (recurrenceRuleOptions.byweekday as Weekday[])
                : [];
            const idx = selectedWeekDays.indexOf(weekday);

            const newSelectedWeekDays =
                idx === -1