How to calculate someone’s age based on the current date vs a string of date

Posted by Maeve Tan on January 4, 2023 at 5:04 pm

So I’m having trouble figuring out this expression. I have to calculate someone’s age from a string that is the birth date(e.g 12/22/1989) based on the current date.

On one text layer, the birthdate string will be inserted and on the other layer, the age should be outputted.

So what I have now is this:

var birthDateString = thisComp.layer("Birth Date");
function dateToCurrentFormat(dateString) {
    var parts = dateString.split(/[/]/);
    var month = Number(parts[0]) - 1; // months are 0-based
    var day = Number(parts[1]);
    var year = Number(parts[2]);
    return new Date(year, month, day);
}

function difference(date1, date2, interval) {
    var second = 1000,
    minute = second * 60,
    hour = minute * 60,
    day = hour * 24,
    week = day * 7;
date1 = new Date(date1);
date2 = new Date(date2);
var timediff = date2 - date1;
if (isNaN(timediff)) return NaN;
switch (interval) {
  case "years":
    return date2.getFullYear() - date1.getFullYear();
  case "months":
    return (
(date2.getFullYear() * 12 + date2.getMonth()) -
(date1.getFullYear() * 12 + date1.getMonth())
);
  case "weeks":
    return Math.floor(timediff / week);
  case "days":
    return Math.floor(timediff / day);
  case "hours":
    return Math.floor(timediff / hour);
  case "minutes":
    return Math.floor(timediff / minute);
  case "seconds":
    return Math.floor(timediff / second);
    default:
    return undefined;
}
}

var birthDate = dateToCurrentFormat(birthDateString);

var age = difference(birthDate, new Date(), "years");

var ageString = age + " years old";
ageString;

Each time I’m getting an error for different things. First, it was “dateToCurrentFormat is not defined” then, ” difference is not defined” and then “object of type found where a Number, Array, or property is needed” for the variable age.

What am I doing wrong here? Maybe I’m doing it more difficult than it should be, if there’s an easier way to get to the result please let me know!
TIA! 🙂

Maeve Tan replied 3 years, 6 months ago 2 Members · 2 Replies

2 Replies

Dan Ebberts

January 4, 2023 at 7:38 pm

I found this one on stackoverflow:

function calculate_age(birth_month,birth_day,birth_year)
{
    today_date = new Date();
    today_year = today_date.getFullYear();
    today_month = today_date.getMonth();
    today_day = today_date.getDate();
    age = today_year - birth_year;
    if ( today_month < (birth_month - 1))
    {
        age--;
    }
    if (((birth_month - 1) == today_month) && (today_day < birth_day))
    {
        age--;
    }
    return age;
}

Maeve Tan
January 5, 2023 at 9:16 am

Thank you I will try this out!

Reply to this Discussion! Login or Sign Up

Creative Communities of the World Forums

How to calculate someone’s age based on the current date vs a string of date