Create ICS files based on input

create-ics.ts

/**
 * @fileoverview Creates an ICS calendar file with recurring events based on provided configuration
 */

import ical, { ICalEventRepeatingFreq, ICalWeekday } from 'ical-generator';
import { writeFileSync } from 'fs';
import { DateTime } from 'luxon';
import yargs from 'yargs';
import { hideBin } from 'yargs/helpers';
import type { ICalRepeatingOptions } from 'ical-generator/dist/index.d.ts';

/**
 * Weekday constants for easier event scheduling
 */
// @ts-ignore
const
  monday = ICalWeekday.MO,
  wednesday = ICalWeekday.WE, 
  saturday = ICalWeekday.SA,
  sunday = ICalWeekday.SU,
  tuesday = ICalWeekday.TU,
  thursday = ICalWeekday.TH,
  friday = ICalWeekday.FR;

/**
 * Array of event configurations
 * @type {Array<{
 *   title: string,
 *   description: string,
 *   start: string, 
 *   end: string,
 *   days: ICalWeekday[]
 * }>}
 */
const events: { title: string; description: string; start: string; end: string; days: ICalWeekday[] }[] = [
  {
    title: "LeetCode Practice",
    description: "Daily coding practice session", 
    start: "19:00",
    end: "20:00",
    days: [sunday, tuesday, thursday, saturday]
  }
];

/**
 * Main function that generates the ICS calendar file
 * @async
 * @returns {Promise<void>} Promise that resolves when the file is written
 */
async function main(): Promise<void> {
    // Parse command line arguments
    const argv = await yargs(hideBin(process.argv))
        .option('repeat', {
            alias: 'r',
            type: 'boolean',
            description: 'Whether the events should repeat',
            default: true,
        })
        .option('duration', {
            alias: 'd', 
            type: 'number',
            description: 'How long the events should repeat (in days)',
            default: 90,
        })
        .option('timezone', {
            alias: 't',
            type: 'string', 
            description: 'Timezone for the events',
            default: 'America/New_York',
        })
        .parseAsync();

    const timezone = argv.timezone;
    const calendar = ical({ name: 'My Schedule', timezone });

    // Calculate start and end dates for events
    const startDate = DateTime.now().setZone(timezone);
    const endDate = argv.repeat ? startDate.plus({ days: argv.duration }) : startDate;

    // Create calendar events
    events.forEach(event => {
        // Configure recurrence rule for repeating events
        const recurrenceRule = {
            freq: ICalEventRepeatingFreq.WEEKLY,
            byDay: event.days.map(day => day),
            until: endDate.toJSDate(),
        } satisfies ICalRepeatingOptions;

        // Calculate event start and end times
        const startTime = DateTime.fromISO(`${startDate.toISODate()}T${event.start}:00`, { zone: timezone });
        const endTime = DateTime.fromISO(`${startDate.toISODate()}T${event.end}:00`, { zone: timezone });

        // Create the calendar event
        calendar.createEvent({
            start: startTime.toJSDate(),
            end: endTime.toJSDate(),
            summary: event.title,
            timezone: timezone,
            repeating: recurrenceRule
        });
    });

    // Write calendar to file
    writeFileSync('schedule.ics', calendar.toString());

    console.log("ICS file generated successfully!");
}

/**
 * Entry point - only run main if this is the main module
 */
if (require.main === module) {
    main().catch(console.error);
}