Provides code that can be used to generate startDateUTC based on a provided date

createStartDateUTC.js

/**
* These are snippets/functions of code used in another app to migrate meeting data from Central to
* an experimental database used by Central Query.
*/

import { DateTime } from "luxon"

enum Weekdays {
  MONDAY = 1,
  TUESDAY,
  WEDNESDAY,
  THURSDAY,
  FRIDAY,
  SATURDAY,
  SUNDAY,
}

const tz = formatTZ(meeting.timezone)

const formatTZ = (tz: string) => {
  const parts = tz.split("/")
  const newParts = parts.map((part) => {
    const subParts = part.split("_")
    const newSubParts = subParts.map((sp) => {
      const ret = ["in", "of"].includes(sp)
        ? sp
        : sp[0].toUpperCase() + sp.substring(1).toLowerCase()
      return ret
    })
    return newSubParts.join("_")
  })
  return newParts.join("/")
}

const updated = dstAware(meeting.time, tz)

const dstAware = (time: string, tz: string) => {
  const localTimeParts = time.split(":")
  const now = DateTime.utc()
  const date = {
    year: now.year,
    month: now.month,
    day: now.day,
    hour: Number(localTimeParts[0]),
    minute: Number(localTimeParts[1]),
  }

  return DateTime.fromObject(date, { zone: tz })
}

const startDateUTC = nextOccurrence(weekday, updated).toJSDate()

const nextOccurrence = (dayOfWeek: Weekdays, dateTime: DateTime) => {
  const adjustedDayOfWeek = dayOfWeek
  const advance = (adjustedDayOfWeek + (7 - dateTime.get("weekday"))) % 7
  const newOrdinalDate = dateTime.ordinal + advance
  return dateTime.set({ ordinal: newOrdinalDate })
}