JavaScript Date time different once deployed to Heroku

Question

Locally, everything is accurate by the minute. Once deployed to Heroku, the difference between the times are off by about 6 hours. I am not looking to convert Heroku time zone (would like it to remain UTC). I've tried everything from getTimezoneOffset() conversions to different date formats and I still end up with the same result. How can I have these 2 date times match each other and not be offset by hours when deployed? Why are they different, when formatted the exact same way?

// Used to calculate current date time

const currentDate = new Date();
// ^ Production - (2021-10-12T19:12:41.081Z)
const time = `${currentDate.getHours()}:${currentDate.getMinutes()}`;
const fullDate = `${currentDate.getMonth()}/${currentDate.getDate()}/${currentDate.getFullYear()}`;
const currentDateFormatted = new Date(`${fullDate} ${time}`);
// ^ Production - (2021-10-12T19:12:00.000Z)

const currentParsedDateToUTC = Date.parse(currentDateFormatted.toUTCString());

// Used to calculate an event date time

const eventDate = new Date(`${event.date} ${event.endTime}`); // same exact format as above
// ^ Production - (2021-10-12T13:12:00.000Z)
const eventParsedDateToUTC = Date.parse(eventDate.toUTCString());

const isExpired = (currentParsedDateToUTC > eventParsedDateToUTC); // works locally, but not in production

In this example, the event date and start time is identical to the current date time. How can I prevent them from being vastly different?

Answer 1

That is because the Heroku server is in a different timezone than yours, you can handle it by converting the time format from your frontend, I recommend you use moment.js for example in your frontend you can convert like this:

npm install moment --save

And then you can create a function just to change the format to display:

const formatDatetime = (
  datetime = "N/A",
  format = 'LLL' // here is your format
) => {
  return moment(datetime).isValid()
    ? moment(datetime).format(format)
    : datetime;
};