Integration Boundary: PureScript Date/Time Libraries ↔ JavaScript Intl API – Interoperability Question

Integration Boundary: PureScript Date/Time Libraries ↔ JavaScript Intl API – Interoperability Question

PureScript exposes a Date type that is a thin wrapper around JavaScript’s native Date, offering only UTC or local time via interop. When parsing an ISO string that includes a time‑zone offset (e.g., 2023-08-01T12:00:00+02:00), the parse function normalises to UTC, discarding the original offset. Formatting that Date with Intl.DateTimeFormat then yields a string whose offset depends on the runtime environment’s locale settings, potentially causing drift between Node.js and browsers.

Because the core library has not yet decided whether to embed a ZoneId component in Date or keep zone handling in a separate module, developers face uncertainty about how to preserve time‑zone semantics across the PureScript‑JavaScript boundary.

Key questions for the community:

• Should the PureScript Date type be extended with an explicit ZoneId field to retain the original offset?
• If not, what is the recommended approach to round‑trip ISO strings with offsets while maintaining consistent formatting across Node.js and browsers?
• What behaviour is expected when a Date parsed from an offset string is formatted with Intl.DateTimeFormat using a different time zone?