Date parsing for fun ~and profit~

date-parser.js

const $classes = `
Mon Apr 3 7pm-10pm (PDT)
Mon Apr 10 7pm-10pm
Mon Apr 17 7pm-10pm
Mon Apr 24 7pm-10pm

$120 USD, 8 (of 8) enrolled
`;

const classes = $classes.split("\n").filter(Boolean);
const priceEnrolled = classes.pop();

for (const c of classes) {
  // TODO: Is this always "PDT" or is it sometimes "PST"?
  const dateParts = c.replace(/\s\(PDT\)$/i, "").trim().split(" ");
  let [startTime, endTime] = dateParts.pop().split("-");
  const [, month, day, year=2023] = dateParts;
  const dateString = [month, day, year].join(" ");
  startTime = new Date(Date.parse(`${dateString} ${isoTime(startTime)}`));
  endTime = new Date(Date.parse(`${dateString} ${isoTime(endTime)}`));
  console.log({
      start: startTime.toISOString(),
      end: endTime.toISOString(),
  });
}

function cleanTime(timeString) {
  if (timeString.includes(":")) {
    return timeString;
  }
  return timeString.replace(/^(\d+)(am|pm)$/i, "$1:00$2");
}

function isoTime(timeString) {
    timeString = cleanTime(timeString);
    let { hour, minute, ampm } = /^(?<hour>\d+):(?<minute>\d{2})(?<ampm>(am|pm))$/i.exec(timeString).groups;
    if (ampm === "pm") {
        hour = (parseInt(hour, 10) + 12) % 24;
    }
    return `${hour}:${minute}`;
}