eleventy.config.js

const ics = require("ics");

const calendar = require("./calendar");

module.exports = (eleventyConfig, options = {}) => {
    eleventyConfig.addFilter("slugifyEvent", (event) => {
        return `${eleventyConfig.getFilter("slugify")(event.data.title)}-${calendar.toHtmlString(event.data.start)}`;
    });

    eleventyConfig.addFilter("toCalendar", (events) => {
        const jsonEvents = (events || []).map(event => calendar.eventToJsonEvent(event, options));
        const {error, value} = ics.createEvents(jsonEvents);
        if (!error) {
            return value;
        }
        console.log(error);
    });

    eleventyConfig.addFilter("toCalendarEvent", (event) => {
        const jsonEvent = calendar.eventToJsonEvent(event, options);
        const {error, value} = ics.createEvent(jsonEvent);
        if (!error) {
            return value;
        }
        console.log(error);
    });
}