Itch.io Jam Page - Add to Google Calendar Userscript

index.js

// ==UserScript==
// @name         Itch Jam Page - Add to Google Calendar
// @namespace    http://tampermonkey.net/
// @version      0.1
// @description  Scrapes date data from jam site and adds a google calendar link
// @author       01010111
// @match        https://itch.io/jam/*
// @icon         https://www.google.com/s2/favicons?sz=64&domain=itch.io
// @grant        none
// ==/UserScript==

(function() {
    'use strict';

    const jam_url = window.location.href;
    const jam_title = document.querySelector('.jam_title_header').innerText;
    const date_data = document.querySelector('.date_data');
    if (!jam_title || !date_data) return;

    const date_format_divs = date_data.querySelectorAll('.date_format');
    const from = new Date(date_format_divs[0].getAttribute('title'));
    const to = new Date(date_format_divs[1].getAttribute('title'));

    function remove_punctuation(input) {
        for (let char of '.-:'.split('')) input = input.replaceAll(char, '');
        return input;
    }

    let base_url = 'https://calendar.google.com/calendar/r/eventedit?action=TEMPLATE';
    let text = `text=${encodeURIComponent(jam_title.trim())}`;
    let dates = `dates=${remove_punctuation(from.toISOString())}/${remove_punctuation(to.toISOString())}`;
    let sprop = `sprop=${encodeURIComponent(jam_url)}`;
    let calendar_url = `${base_url}&${text}&${dates}&${sprop}`;
    if (!text || !dates || !sprop) return;

    date_data.onclick = () => window.open(calendar_url,'_blank');
    date_data.style.cursor = 'pointer';
})();