You can generate a date convert function as follows:

var convert = scheduler.date.date_to_str("%format%");
some_string = convert( date_object );

Backward convertion can be achieved as follows:

var convert = scheduler.date.str_to_date("%format%");
date_object = convert( date_as_string );

Both functions can be used in UTC variation

//convert date object in local time to string in UTC time
var convert = scheduler.date.date_to_str("%format%",true);
//convert string in UTC time to date object in local time
var convert = scheduler.date.str_to_date("%format%",true);

var new_date = scheduler.data.add(date,increment,unit);
 
//next month
var new_date = scheduler.data.add(date,1,"month");
 
//previous week
var new_date = scheduler.data.add(date,-1,"week");

Supported units are: day, week, month, year, hour, minute