有没有可以处理重复（RRULE）事件的节点读卡器？

Question

使用此演示日历：

对于日历阅读器，输出如下所示：

但是从 npm 上的各种节点项目及其各种分支中，我得到的只是：

On 2018-10-09, Event repeating monthly on 2nd tuesday at 10am
On 2018-10-10, Event repeating weekly on a Wednesday at 11am
On 2018-10-11, Single event on 11th October

代码如下 - 一些额外的内容，因为我只对未来的日期感兴趣，并且很高兴按照即将到来的日期顺序排列事物，而不是随机的

const ical = require('ical');
var dateNow = new Date();

const url = "https://calendar.google.com/calendar/ical/ssjqjrg27h9mqqctfnr5kscmrk%40group.calendar.google.com/public/basic.ics";

  ical.fromURL(url, {}, function (err, data) {
    var ttsorted = [];
    for (const k in data) {
      const ev = data[k];
      const eventStart = new Date(ev.start);
      if (data.hasOwnProperty(k)) {
      if (eventStart.getTime() >= dateNow.getTime()) {
          const tts = `On ${ev.start.toISOString().slice(0,10)}, ${ev.summary} `;
          ttsorted.push(tts);
        }
     }
    }
    ttsorted.sort();
    for (const events of ttsorted) {
      console.log(events);
    }
  });

Answer 1

当前的 node-ical 包可以确定在给定时间/日期范围内发生哪些重复事件。在为最终用户准备好时间之前，您最终需要自己进行一些数据处理。

来自包文档：

const ical = require('node-ical');
const moment = require('moment-timezone');

ical.fromURL('http://lanyrd.com/topics/nodejs/nodejs.ics', {}, function (err, data) {
    for (let k in data) {
        if (!Object.prototype.hasOwnProperty.call(data, k)) continue;

        const event = data[k];
        if (event.type !== 'VEVENT' || !event.rrule) continue;
        
        const dates = event.rrule.between(new Date(2021, 0, 1, 0, 0, 0, 0), new Date(2021, 11, 31, 0, 0, 0, 0))
        if (dates.length === 0) continue;

        console.log('Summary:', event.summary);
        console.log('Original start:', event.start);
        console.log('RRule start:', `${event.rrule.origOptions.dtstart} [${event.rrule.origOptions.tzid}]`)

        dates.forEach(date => {
            let newDate
            if (event.rrule.origOptions.tzid) {
                // tzid present (calculate offset from recurrence start)
                const dateTimezone = moment.tz.zone('UTC')
                const localTimezone = moment.tz.guess()
                const tz = event.rrule.origOptions.tzid === localTimezone ? event.rrule.origOptions.tzid : localTimezone
                const timezone = moment.tz.zone(tz)
                const offset = timezone.utcOffset(date) - dateTimezone.utcOffset(date)
                newDate = moment(date).add(offset, 'minutes').toDate()
            } else {
                // tzid not present (calculate offset from original start)
                newDate = new Date(date.setHours(date.getHours() - ((event.start.getTimezoneOffset() - date.getTimezoneOffset()) / 60)))
            }
            const start = moment(newDate)
            console.log('Recurrence start:', start)
        })

        console.log('-----------------------------------------------------------------------------------------');
    }
});