Update the Date in case it's before 2020 due to lapped old GPS.

[htool]

In case of old GPS, the Date part of the pgn will be < 2020. This corrects that, as this pgn should not give a Date < 2020.

[tkurki]

The only problem I see would be parsing data that was captured before the rollover. For that we could have an environment variable to switch this optionally off, but I guess we'll cross that bridge if somebody needs it.

[htool]

Agreed. I first tried to fix it further upstream, but that made some tests fail where Date is use to tell age of certain info.
Hence the somewhat suboptimal re-parsing of the string.

[tkurki]

Can I interest you in adding a test for this? see test/129029.js

[goergevo]

Thank you for this code! I have the same problem with the old GPS on my boat.
I noticed that the code for PGN 126992 has to be changed as well.
And for padding you can use String( ).padStart(2, '0') so you don't need that extra padding function.

[goergevo]

I checked your conversion code an its indeed one day wrong.
"2002-11-18" should be converted to "2022-07-04", but the output is "2022-07-03".

I think its better to base the calculation on ms, this code works correctly:

isoDateString = "2002-11-18T20:13:03Z";     // The original date string from GPS
console.log("old: " + isoDateString);
// expected output: "2022-07-04T20:13:03Z"

// Parse the input ISO date string
const datePart = isoDateString.split('T')[0]; // Extract the date part (YYYY-MM-DD)
const timePart = isoDateString.split('T')[1]; // Extract the time part (HH:mm:ssZ)

// Create a new Date object from the date part
const date = new Date(datePart);

const compensationWeeks = 1024; // Number of weeks to add to the date

// Check if the year is earlier than 2020
const year = date.getUTCFullYear();
if (year < 2020) {
    // Calculate the number of milliseconds in 1024 weeks
    const millisecondsInAWeek = 7 * 24 * 60 * 60 * 1000;
    const millisecondsToAdd = compensationWeeks * millisecondsInAWeek;
    
    // Add the milliseconds to the date
    date.setTime(date.getTime() + millisecondsToAdd);

    // Extract the new date components
    const newYear = date.getUTCFullYear();
    const newMonth = String(date.getUTCMonth() + 1).padStart(2, '0');
    const newDay = String(date.getUTCDate()).padStart(2, '0');

    // Construct the new ISO date string
    // expected output: "2022-07-04T20:13:03Z"
    isoDateString = `${newYear}-${newMonth}-${newDay}T${timePart}`;
}
console.log("new: " + isoDateString);

[htool]

I'm not sure the above works. In case the date is corrected, the timestamp will be now() and the data in the packet will remain old and reaches SignalK, right?