tc39-times.js

// deno run https://gist.githubusercontent.com/ryzokuken/4f3b856cae68c592e297cdf495816613/raw/3a82c748a6648af518dc9e816f08a3a513d19911/tc39-times.js <date> <timezone>

import { Temporal } from "npm:@js-temporal/polyfill";

const startTime = Temporal.PlainTime.from("10:00");
const inputDate = Deno.args[0];
if (inputDate === undefined) throw Error("must provide a start date");
const inputTz = Deno.args[1];
if (inputTz === undefined) throw Error("must provide a meeting timezone");
const startDate = Temporal.PlainDate.from(inputDate);
const days = 4;

const showTimeZones = [
  // CLDR abbreviations are locale specific so we need to provide different locales for the desired short TZ names
  ["America/Los_Angeles", "en-US"],
  ["America/Chicago", "en-US"],
  ["Europe/London", "en-GB"],
  ["Europe/Madrid", "es-ES"],
];

const formatOptions = {
  hour: "2-digit",
  hour12: false,
  hourCycle: "h23",
  minute: "2-digit",
};

const baseTime = startDate.toZonedDateTime({
  timeZone: inputTz,
  plainTime: startTime,
});

function spans(time, tz) {
  time = time.withTimeZone(tz);
  return {
    am: [time, time.add({ hours: 2 })],
    pm1: [time.add({ hours: 3 }), time.add({ hours: 5 })],
    pm2: [time.add({ hours: 5 }), time.add({ hours: 7 })],
  };
}

function formatSpan(span, locale) {
  return `${
    span[0].toLocaleString(
      locale,
      formatOptions,
    )
  }-${
    span[1].toLocaleString(locale, {
      ...formatOptions,
      timeZoneName: "short",
    })
  }`;
}

let current = baseTime;
const timeRow = [];
for (let i = 0; i < days; i++) {
  let amText = [];
  let pm1Text = [];
  let pm2Text = [];

  for (const zone of showTimeZones) {
    const [z, l] = zone;
    const zoneSpans = spans(current, z);
    amText.push(formatSpan(zoneSpans.am, l));
    pm1Text.push(formatSpan(zoneSpans.pm1, l));
    pm2Text.push(formatSpan(zoneSpans.pm2, l));
  }

  timeRow.push(
    current.toPlainDate().toString(),
    amText.join("\n"),
    pm1Text.join("\n"),
    pm2Text.join("\n"),
  );

  current = current.add({ days: 1 });
}

console.log(timeRow.join("\n\n"));