docs/site_libs/quarto-listing/quarto-listing.js

const kProgressiveAttr = "data-src";
let categoriesLoaded = false;

window.quartoListingCategory = (category) => {
  // category is URI encoded in EJS template for UTF-8 support
  category = decodeURIComponent(atob(category));
  if (categoriesLoaded) {
    activateCategory(category);
    setCategoryHash(category);
  }
};

window["quarto-listing-loaded"] = () => {
  // Process any existing hash
  const hash = getHash();

  if (hash) {
    // If there is a category, switch to that
    if (hash.category) {
      // category hash are URI encoded so we need to decode it before processing
      // so that we can match it with the category element processed in JS
      activateCategory(decodeURIComponent(hash.category));
    }
    // Paginate a specific listing
    const listingIds = Object.keys(window["quarto-listings"]);
    for (const listingId of listingIds) {
      const page = hash[getListingPageKey(listingId)];
      if (page) {
        showPage(listingId, page);
      }
    }
  }

  const listingIds = Object.keys(window["quarto-listings"]);
  for (const listingId of listingIds) {
    // The actual list
    const list = window["quarto-listings"][listingId];

    // Update the handlers for pagination events
    refreshPaginationHandlers(listingId);

    // Render any visible items that need it
    renderVisibleProgressiveImages(list);

    // Whenever the list is updated, we also need to
    // attach handlers to the new pagination elements
    // and refresh any newly visible items.
    list.on("updated", function () {
      renderVisibleProgressiveImages(list);
      setTimeout(() => refreshPaginationHandlers(listingId));

      // Show or hide the no matching message
      toggleNoMatchingMessage(list);
    });
  }
};

window.document.addEventListener("DOMContentLoaded", function (_event) {
  // Attach click handlers to categories
  const categoryEls = window.document.querySelectorAll(
    ".quarto-listing-category .category"
  );

  for (const categoryEl of categoryEls) {
    // category needs to support non ASCII characters
    const category = decodeURIComponent(
      atob(categoryEl.getAttribute("data-category"))
    );
    categoryEl.onclick = () => {
      activateCategory(category);
      setCategoryHash(category);
    };
  }

  // Attach a click handler to the category title
  // (there should be only one, but since it is a class name, handle N)
  const categoryTitleEls = window.document.querySelectorAll(
    ".quarto-listing-category-title"
  );
  for (const categoryTitleEl of categoryTitleEls) {
    categoryTitleEl.onclick = () => {
      activateCategory("");
      setCategoryHash("");
    };
  }

  categoriesLoaded = true;
});

function toggleNoMatchingMessage(list) {
  const selector = `#${list.listContainer.id} .listing-no-matching`;
  const noMatchingEl = window.document.querySelector(selector);
  if (noMatchingEl) {
    if (list.visibleItems.length === 0) {
      noMatchingEl.classList.remove("d-none");
    } else {
      if (!noMatchingEl.classList.contains("d-none")) {
        noMatchingEl.classList.add("d-none");
      }
    }
  }
}

function setCategoryHash(category) {
  setHash({ category });
}

function setPageHash(listingId, page) {
  const currentHash = getHash() || {};
  currentHash[getListingPageKey(listingId)] = page;
  setHash(currentHash);
}

function getListingPageKey(listingId) {
  return `${listingId}-page`;
}

function refreshPaginationHandlers(listingId) {
  const listingEl = window.document.getElementById(listingId);
  const paginationEls = listingEl.querySelectorAll(
    ".pagination li.page-item:not(.disabled) .page.page-link"
  );
  for (const paginationEl of paginationEls) {
    paginationEl.onclick = (sender) => {
      setPageHash(listingId, sender.target.getAttribute("data-i"));
      showPage(listingId, sender.target.getAttribute("data-i"));
      return false;
    };
  }
}

function renderVisibleProgressiveImages(list) {
  // Run through the visible items and render any progressive images
  for (const item of list.visibleItems) {
    const itemEl = item.elm;
    if (itemEl) {
      const progressiveImgs = itemEl.querySelectorAll(
        `img[${kProgressiveAttr}]`
      );
      for (const progressiveImg of progressiveImgs) {
        const srcValue = progressiveImg.getAttribute(kProgressiveAttr);
        if (srcValue) {
          progressiveImg.setAttribute("src", srcValue);
        }
        progressiveImg.removeAttribute(kProgressiveAttr);
      }
    }
  }
}

function getHash() {
  // Hashes are of the form
  // #name:value|name1:value1|name2:value2
  const currentUrl = new URL(window.location);
  const hashRaw = currentUrl.hash ? currentUrl.hash.slice(1) : undefined;
  return parseHash(hashRaw);
}

const kAnd = "&";
const kEquals = "=";

function parseHash(hash) {
  if (!hash) {
    return undefined;
  }
  const hasValuesStrs = hash.split(kAnd);
  const hashValues = hasValuesStrs
    .map((hashValueStr) => {
      const vals = hashValueStr.split(kEquals);
      if (vals.length === 2) {
        return { name: vals[0], value: vals[1] };
      } else {
        return undefined;
      }
    })
    .filter((value) => {
      return value !== undefined;
    });

  const hashObj = {};
  hashValues.forEach((hashValue) => {
    hashObj[hashValue.name] = decodeURIComponent(hashValue.value);
  });
  return hashObj;
}

function makeHash(obj) {
  return Object.keys(obj)
    .map((key) => {
      return `${key}${kEquals}${obj[key]}`;
    })
    .join(kAnd);
}

function setHash(obj) {
  const hash = makeHash(obj);
  window.history.pushState(null, null, `#${hash}`);
}

function showPage(listingId, page) {
  const list = window["quarto-listings"][listingId];
  if (list) {
    list.show((page - 1) * list.page + 1, list.page);
  }
}

function activateCategory(category) {
  // Deactivate existing categories
  const activeEls = window.document.querySelectorAll(
    ".quarto-listing-category .category.active"
  );
  for (const activeEl of activeEls) {
    activeEl.classList.remove("active");
  }

  // Activate this category
  const categoryEl = window.document.querySelector(
    `.quarto-listing-category .category[data-category='${btoa(
      encodeURIComponent(category)
    )}']`
  );
  if (categoryEl) {
    categoryEl.classList.add("active");
  }

  // Filter the listings to this category
  filterListingCategory(category);
}

function filterListingCategory(category) {
  const listingIds = Object.keys(window["quarto-listings"]);
  for (const listingId of listingIds) {
    const list = window["quarto-listings"][listingId];
    if (list) {
      if (category === "") {
        // resets the filter
        list.filter();
      } else {
        // filter to this category
        list.filter(function (item) {
          const itemValues = item.values();
          if (itemValues.categories !== null) {
            const categories = decodeURIComponent(
              atob(itemValues.categories)
            ).split(",");
            return categories.includes(category);
          } else {
            return false;
          }
        });
      }
    }
  }
}