.eleventy.js

const htmlmin = require('html-minifier')
const UpgradeHelper = require("@11ty/eleventy-upgrade-help");
const { DateTime } = require("luxon");
const fs = require("fs");
const pluginRss = require("@11ty/eleventy-plugin-rss");
const pluginSyntaxHighlight = require("@11ty/eleventy-plugin-syntaxhighlight");
const pluginNavigation = require("@11ty/eleventy-navigation");
const markdownIt = require("markdown-it");
const markdownItAnchor = require("markdown-it-anchor");


module.exports = function(eleventyConfig) {
    /**
     * Upgrade helper
     * Uncomment if you need help upgrading to new major version.
     */
    //eleventyConfig.addPlugin(UpgradeHelper);

    /**
     * Files to copy
     * https://www.11ty.dev/docs/copy/
     */
    eleventyConfig.addPassthroughCopy('src/img')
        // Add plugins
    eleventyConfig.addPlugin(pluginRss);
    eleventyConfig.addPlugin(pluginSyntaxHighlight);
    eleventyConfig.addPlugin(pluginNavigation);

    eleventyConfig.addFilter("readableDate", dateObj => {
        return DateTime.fromJSDate(dateObj, { zone: 'utc' }).toFormat("dd LLL yyyy");
    });

    // https://html.spec.whatwg.org/multipage/common-microsyntaxes.html#valid-date-string
    eleventyConfig.addFilter('htmlDateString', (dateObj) => {
        return DateTime.fromJSDate(dateObj, { zone: 'utc' }).toFormat('yyyy-LL-dd');
    });

    // Get the first `n` elements of a collection.
    eleventyConfig.addFilter("head", (array, n) => {
        if (!Array.isArray(array) || array.length === 0) {
            return [];
        }
        if (n < 0) {
            return array.slice(n);
        }

        return array.slice(0, n);
    });

    // Return the smallest number argument
    eleventyConfig.addFilter("min", (...numbers) => {
        return Math.min.apply(null, numbers);
    });

    function filterTagList(tags) {
        return (tags || []).filter(tag => ["all", "nav", "post", "posts"].indexOf(tag) === -1);
    }

    eleventyConfig.addFilter("filterTagList", filterTagList)

    // Create an array of all tags
    eleventyConfig.addCollection("tagList", function(collection) {
        let tagSet = new Set();
        collection.getAll().forEach(item => {
            (item.data.tags || []).forEach(tag => tagSet.add(tag));
        });

        return filterTagList([...tagSet]);
    });

    // Customize Markdown library and settings:
    let markdownLibrary = markdownIt({
        html: true,
        breaks: true,
        linkify: true
    }).use(markdownItAnchor, {
        permalink: markdownItAnchor.permalink.ariaHidden({
            placement: "after",
            class: "direct-link",
            symbol: "#",
            level: [1, 2, 3, 4],
        }),
        slugify: eleventyConfig.getFilter("slug")
    });
    eleventyConfig.setLibrary("md", markdownLibrary);


    // Override Browsersync defaults (used only with --serve)
    eleventyConfig.setBrowserSyncConfig({
        callbacks: {
            ready: function(err, browserSync) {
                const content_404 = fs.readFileSync('_site/404.html');

                browserSync.addMiddleware("*", (req, res) => {
                    // Provides the 404 content without redirect.
                    res.writeHead(404, { "Content-Type": "text/html; charset=UTF-8" });
                    res.write(content_404);
                    res.end();
                });
            },
        },
        ui: false,
        ghostMode: false
    });





    /**
     * HTML Minifier for production builds
     */
    eleventyConfig.addTransform('htmlmin', function(content, outputPath) {
        if (
            process.env.ELEVENTY_ENV == 'production' &&
            outputPath &&
            outputPath.endsWith('.html')
        ) {
            let minified = htmlmin.minify(content, {
                useShortDoctype: true,
                removeComments: true,
                collapseWhitespace: true,
            })
            return minified
        }

        return content
    })

    return {
        dir: {
            input: "src",
            data: "_data",
        }
    };
};