Parameterize or reuse collection?

[j9t]

Massive brain fog, help appreciated: Have some already complex double pagination collection in my .eleventy.js,

// Create (date-sorted) collection for tag pagination, https://github.com/11ty/eleventy/issues/332#issuecomment-445236776
eleventyConfig.addCollection("doublePagination", function(collectionApi) {
  let tagSet = new Set();
  collectionApi.getAllSorted().sort((a, b) => (Number(a.data.date_publication) > Number(b.data.date_publication) ? 1 : -1)).map(function(item) {
    if ("tags" in item.data) {
      let tags = item.data.tags;
      for (let tag of tags) {
        tagSet.add(tag);
      }
    }
  });

  // Remove tags from tag set
  tagSet.delete("posts");

  // Get each item that matches the tag
  let paginationSize = 250;
  let tagMap = [];
  let tagArray = [...tagSet];
  for (let tagName of tagArray) {
    // Retrieve all items with the tag
    let tagItems = collectionApi.getFilteredByTag(tagName);
    // Fix invalid dates (from tools)
    for (let i = 0; i < tagItems.length; i++) {
      if (!DateTime.fromJSDate(tagItems[i].data.date_publication).isValid) {
        tagItems[i].data.date_publication = new Date(2020,1,1);
      }
    }
    // Convert dates and sort by them
    tagItems.sort((a, b) => b.data.date_publication.toISOString().localeCompare(a.data.date_publication.toISOString()));
    // Break into pages
    let pagedItems = lodash.chunk(tagItems, paginationSize);
    for (let pageNumber = 0, max = pagedItems.length; pageNumber < max; pageNumber++) {
      tagMap.push({
        tagName: tagName,
        pageNumber: pageNumber,
        pageData: pagedItems[pageNumber]
      });
    }
  }

  return [...tagMap];
});

For a related issue I need the same collection, but without or with a different paginationSize.

Is it possible to pass on a parameter to the collection to define/change the pagination size, or to make this reusable so that two collections could be based on the code?

The first doesn’t seem to be possible at all, but even if I move the code above into a function that I call from two new collections, akin to the below pseudo code, I cannot get this to work:

eleventyConfig.addCollection("foo1", function(collectionApi) { bar("size1") }
eleventyConfig.addCollection("foo2", function(collectionApi) { bar("size2") }
function bar(size) { /* all the collection logic */ }

As I work on setting up tag feeds I (think I) rely on the respective collection logic, but I may miss something obvious. Thank you!

[j9t]

That was all foggy indeed.

While the question of “parameterizing” a collection is still open, I managed to solve the problem itself by using an existing collection […].