Create a TZDate instance from an IsoString with offset

[gbalduzzi]

From an external service, I receive time strings in the iso format, containing the timezone offset:

2024-09-12T00:00:00Z+02:00
2024-09-12T00:00:00Z-05:00

date-fns parseIso correctly process the timezone, but converts the Date into the browser timezone.

Is there a way to obtain a proper TZDate instance from such an isoString?

In the documentation I can only see ways to build a TZDate when you already know the desidered timezone in advance

[jonathanstanley]

I had the same question and couldn't find a solution in the docs. @date-fns Is there a reason there isn't a function like this?

/** returns a TZDate using the timezone of the ISO 8601 string */
export const parseWithTz = (iso: string) => {
  const offset = iso.match(/([-+])(\d{2}):(\d{2})$/)?.at(0);
  return new TZDate(iso, offset);
};

let example = "2024-01-12T01:10:10.110-06:00";
console.log(parseWithTz(example).toISOString()); // 2024-01-12T01:10:10.110-06:00 ✅ identical
console.log(new TZDate(example).toISOString()) // ❌ drops/loses original offset and outputs local/sys offset