Extendscript and Date Formats

[Marshall_Brooks]

I think this will be a difficult question.

I have a document that must have a date as 20230517 in one location and as 5 May 2023 in another location.

This is a publication date, but not necessarily today's date, nor the creation date.

We use user variables - for example "DateYearFirst" and "DateD-M-Y" for the two dates and update them manually.

I know if VBA, there are format codes that can change the date format.

Does anyone know of a way to set up either Extendscript or the template so that when the YYYYMMDD variable is updated, the d Mmm YYYY date variable is also updated?
Something like an OnChange event for the variable.

[Marshall_Brooks]

@frameexpert Rick - cross-posting with https://community.adobe.com/t5/indesign-discussions/validating-data-in-scriptui/m-p/13817022#M528102 - but ...
Your conversion code works great - although I don't really understand it.
Would you mind putting together a code snippet to verify a string is a valid YYYYMMDD date. I have links to code in the other thread that doesn't work, and it seems like your code would pretty much be doing this to do the conversion.

[Marshall_Brooks]

I figured it out!!!

Used a combination of Rick's code and the nscaler code:

var date, dateObj;

date = "20230525";

dateObj = IsValidDate(date);
alert (dateObj);


function IsValidDate(date) {
// Finds dates between 2000 and 2199 as valid.    
    var regex, matches, dateObj;
    
    // Regular expression for parsing YYYYMMDD date.
    regex = /^(\d{2})(\d{2})(\d{2})(\d{2})$/;
    
    if (regex.test (date) === true) {
        matches = date.match (regex);
        dateObj = {};
        dateObj.century = matches[1];
        if (dateObj.century < 20 || dateObj.century > 21){
            return false;
            }
        dateObj.partyear = matches[2];
        dateObj.year = dateObj.century + dateObj.partyear;
        dateObj.monthPadded = matches[3];
        dateObj.month = Number (dateObj.monthPadded.replace (/^0+/, ""));
        dateObj.dayPadded = matches[4];
        dateObj.day = Number (dateObj.dayPadded.replace (/^0+/, ""));
        // Define the number of days per month
        var daysInMonth = [0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31];
        // Leap years
        if (dateObj.year % 400 == 0 || (dateObj.year % 100 != 0 && dateObj.year % 4 == 0)) {
            daysInMonth[2] = 29;
        }
        if (dateObj.month < 1 || dateObj.month > 12 || dateObj.day < 1 || dateObj.day > daysInMonth[dateObj.month]) {
            return false;
        }
    return true;   
     } return false;
}

Probably not the cleanest way to do it, but it works!

[Marshall_Brooks]

I'm back again, I'm having a hard time finding a function to add 1 year or 2 years to a specified YYYYMMDD date.

IOW, I'm looking for something like:

var date, newdate;

date = "20230525"

function addDays(date, days) {

// some code;

return result;

}

newdate = addDays(date, 365) should return 20240530.

newdate = addDays(date, 730) should return 20240530.

There are a lot of examples at https://stackoverflow.com/questions/563406/how-to-add-days-to-date but the one that ALMOST works is:

var theDate = new Date(20230531);
var myNewDate = new Date(theDate);
myNewDate.setDate(myNewDate.getDate() + 365);
alert(myNewDate);

but it comes out a month ahead.

I think I need to convert the date into some format that JS understands, then get the millisecond date from that using GetDate, then use SetDate to add the days, then convert the output back to YYYYMMDD - but I'm pretty fuzzy on how to do that.

[Marshall_Brooks · Accepted solution]

I figured it out, but the code could I'm sure be cleaner and more simplified, but it works.

I started with this code:

function addDays(myDate,days) {
return new Date(myDate.getTime() + days*24*60*60*1000);
}
var myDate = new Date('2013-02-11');
var newDate = addDays(myDate,5);

From https://stackoverflow.com/questions/14842526/add-days-to-date-format-yyyy-mm-dd Note that although the thread specifically asks for format YYYYMMDD, and the example shows YYYY-MM-DD, it doesn't actually work, it returns a date in 1916 (!!!???!!!), but if you change the input to MM-DD-YYYY, it works properly, although it just gives you the GMT value.

I combined that with Rick's parser that was posted previously and some code that I stole (errrm acquired) from https://www.w3resource.com/javascript-exercises/javascript-basic-exercise-3.php and came up with:

var date, newdate;
date = "20230601"
var newdate = addDays(date, 365);
alert(newdate);

function addDays(date, days) {
    var regex, matches, dateObj;
    // Regular expression for parsing YYYYMMDD date.
    regex = /^(\d{4})(\d{2})(\d{2})$/;  
    if (regex.test (date) === true) {
        matches = date.match (regex);
        dateObj = {};
        dateObj.year = matches[1];
        dateObj.monthPadded = matches[2];
        dateObj.dayPadded = matches[3];
        var initialDate=dateObj.monthPadded + "-" + dateObj.dayPadded + "-" + dateObj.year
        var myDate = new Date(initialDate)
        var ResultDate = new Date(myDate.getTime() + days*24*60*60*1000)
        var dd = ResultDate.getDate();
        var mm = ResultDate.getMonth()+1; 
        var yyyy = ResultDate.getFullYear();
        if(dd<10) {
            dd='0'+dd;
        } 
        if(mm<10) {
            mm='0'+mm;
        } 
        var outputdate = yyyy+mm+dd;        
        return outputdate;        
        } 
}

Like I said, I'm sure there are more efficient ways to do it, but it works!