Eleventy Filter (getWebmentions.js)

getWebmentions.js

const site = {
    url: "https://example.com"
}

const absoluteURL = function(url, base) {
    if (!base) {
        base = site.url
    }
    try {
        return (new URL(url, base)).toString()
    } catch(e) {
        console.log(`Trying to convert ${url} to be an absolute url with base ${base} and failed.`);
        return url
    }
};

module.exports = function(eleventyConfig) {
    eleventyConfig.addFilter("getWebmentions", (webmentions, url, allowedTypes) => {
        url = absoluteURL(url)

        if (!url || !webmentions.mentions || !webmentions.mentions[url]) {
            return []
        }

        if (!allowedTypes) {
            allowedTypes = ["like-of", "repost-of", "bookmark-of", "mention-of", "in-reply-to"]
        }
        else if (typeof allowedTypes === "string") {
            allowedTypes = [allowedTypes]
        }

        const allowedHTML = {
            allowedTags: ['b', 'i', 'em', 'strong', 'a'],
            allowedAttributes: {
                a: ['href']
            }
        }

        return webmentions.mentions[url]
            .filter(entry => {
                return allowedTypes.includes(entry["wm-property"])
            })
            .filter((entry) => {
                const { author } = entry
                return !!author && !!author.name
            })
            .map(entry => {
                if (!("content" in entry)) {
                    return entry
                }
                const { html, text } = entry.content
                if (html) {
                    // really long html mentions, usually newsletters or compilations
                    entry.content.value =
                        html.length > 2000
                            ? `mentioned this in <a href="${entry['wm-source']}">${entry['wm-source']}</a>`
                            : sanitizeHTML(html, allowedHTML)
                }
                else {
                    entry.content.value = sanitizeHTML(text, allowedHTML)
                }
                return entry
            })
    })
}