addCouchsurfingEvent.js

(function () {

    function loadScript(url) {

        return new Promise((resolve) => {

            let script = document.createElement('script');
            script.type = 'text/javascript';
            script.async = false;
            script.src = url;
            script.onload = () => {
                resolve('loaded');
            };
            let firstScript = document.getElementsByTagName('script')[0];
            firstScript.parentNode.insertBefore(script, firstScript);
        });
    }

    Promise.all([
        loadScript('https://cdnjs.cloudflare.com/ajax/libs/moment.js/2.14.1/moment.min.js'),
        loadScript('https://cdnjs.cloudflare.com/ajax/libs/ramda/0.22.1/ramda.min.js')
    ]).then(() => {


        let _ = R;

        let couchSurferName = document.querySelector('.cs-inbox-thread-header-user-info h1').textContent,
            arriveDate = moment(document.querySelector('.couch-visit__details > p').textContent.split(' - ')[0]),
            howManyDays = Number(document.querySelector('.couch-visits-nights').textContent.match(/\d+/gi)[0]),
            leavingDate = _.clone(arriveDate).add(howManyDays, 'day'),
            eventTitle = `CouchSurfing ${couchSurferName}`,
            dates = _.map(
                _.pipe(
                    (date) => date.year(moment().year()),
                    (date) => date.format('YYYYMMDD')
                ), [arriveDate, leavingDate]).join('/');

        let eventParams = {
                action: 'TEMPLATE',
                text: eventTitle,
                dates: dates,
                sprop: 'name:Name&sprop=website:EventWebite',
                sf: 'true',
                output: 'xml'
            },
            objectAsURI = (obj) => {
                return _.pipe(
                    _.map(_.join('=')),
                    _.join('&')
                )
                (_.zip(_.keys(obj), _.values(obj)));
            },

            googleCalendarNewEventUrl = _.concat('https://www.google.com/calendar/render?', objectAsURI(eventParams));

        window.open(googleCalendarNewEventUrl);

    });
}());