pub.solar/hakken-dates.js

(() => {
  const skippedMonths = [
    { m: 8, y: 2022 },
    { m: 12, y: 2022 },
  ];

  const i18n = {
    en: {
      comingDates: 'The following dates are scheduled:',
      friday: 'friday',
      sunday: 'sunday',
      until: 'until',
      months: [
        'Jan.',
        'Feb.',
        'Mar.',
        'Apr.',
        'May',
        'Jun.',
        'Jul.',
        'Aug.',
        'Sep.',
        'Oct.',
        'Nov.',
        'Dec.',
      ],
    },
    de: {
      comingDates: 'Folgende Termine stehen an:',
      friday: 'Freitag',
      sunday: 'Sonntag',
      until: 'bis',
      months: [
        'Jan.',
        'Feb.',
        'Mär.',
        'Apr.',
        'Mai',
        'Jun.',
        'Jul.',
        'Aug.',
        'Sep.',
        'Okt.',
        'Nov.',
        'Dez.',
      ],
    },
  };

  const datesLists = {
    en: document.getElementById('dates-list-en'),
    de: document.getElementById('dates-list-de'),
  };

  const day = 24 * 60 * 60 * 1000;
  const week = 7 * day;
  const endOfWeekend = 2 * day;
  const start = new Date();
  const hakkens = [];
  // We'll be looking about half a year into the future
  for (let i = 0; i < 185; i++) {
    const dateToTry = new Date(start.valueOf() + (i * day));
    if (dateToTry.getDay() !== 5) {
      continue;
    }

    const oneWeekLater = new Date(dateToTry.valueOf() + week);
    if (dateToTry.getMonth() === oneWeekLater.getMonth()) {
      continue;
    }

    const m = dateToTry.getMonth() + 1;
    const y = dateToTry.getFullYear();
    if (skippedMonths.find((s) => s.m === m && s.y === y)) {
      continue;
    }
    hakkens.push(dateToTry);
  }

  // Helper function to add leading zeros to dates
  const d = (num) => ('0' + num).slice(-2);

  const writeText = (lang) => {
    const p = document.createElement('p');
    p.innerHTML = i18n[lang].comingDates;
    datesLists[lang].appendChild(p);
  }

  const writeDateList = (lang) => {
    const ul = document.createElement('ul');
    hakkens.forEach(hakken => {
      hakkend = new Date(hakken.valueOf() + endOfWeekend);
      const showFirstMonth = hakken.getMonth() !== hakkend.getMonth();
      const li = document.createElement('li');
      li.innerHTML = `
        ${i18n[lang].friday} ${d(hakken.getDate())}. ${showFirstMonth ? i18n[lang].months[hakken.getMonth()] : ''}
        ${i18n[lang].until}
        ${d(hakkend.getDate())}. ${i18n[lang].months[hakkend.getMonth()]}
      `;
      ul.appendChild(li);
    });
    datesLists[lang].appendChild(ul);
  }

  writeText('de');
  writeText('en');
  writeDateList('de');
  writeDateList('en');
})();