dateFunctions

        function DateFunctions(date1, date2)
        {
            this.date1 = new Date(date1);
            this.date2 = new Date(date2);

            this.format = function(date = this.date1){

                return `${date.getDate()}.${date.getMonth()+1}.${date.getFullYear()}`
            }

             this.different_date_in_timeshtamp = function(d1, d2) {
                return Math.abs(+d1 - +d2);
            },
            this.timestamp_to_days = function(bigInt) {
              return Math.round(bigInt/(1000*60*60*24));

            },
            this.different_date_in_days = function(date1, date2) {
                ms = this.different_date_in_timeshtamp(date1, date2);
              return this.timestamp_to_days(ms);
            },
            this.getLastWeekDate = function() {
              date = new Date();
              date.setDate(date.getDate() - 7);
              return this.format(date);
            }
        }

        let date_functions = new DateFunctions('2019-10-11', '2019-11-08');
        console.log(date_functions.format(new Date()))