在 JavaScript 中，用于解析特定字符串的正确“时间”类型是什么？

Question

ECMAScript's new Temporal proposal defines (finally!) a modern API for handling dates and times in JS, including timezone-safe arithmetic and non-Gregorian calendars.

I know I can use ISO 8601 or RFC 3339 strings with Temporal . If I have string data that I want to parse into a JS date/time object, which Temporal type should I use?

Answer 1

To determine the Temporal class that should be used to parse a string, it's important to pick the type whose data model matches the data in the string.

• Temporal.Instant represents an exact time. Its data model is the number of integer nanoseconds since January 1, 1970 UTC. This type is unaware of time zones and does not provide a way to access calendar/clock units like month or hour. It's just a timestamp.
• Temporal.ZonedDateTime represents an exact time from the perspective of a specific time zone. Its data model is a timestamp (like Temporal.Instant ), a time zone (usually an IANA zone), and a calendar. The time zone is needed because this Temporal type (and only this type) allows DST-safe creation of derived values. When you add 1 day to a Temporal.ZonedDateTime instance, the exact time will usually be 24 hours later but it may be 23 or 25 if the addition crossed a DST transition.
• Temporal.PlainDate represents a timezone-less date: a local date without a time and without any reference to the time zone. Its data model is a year/month/day and a calendar.
• Temporal.PlainMonthDay represents a birthday, anniversary, or other recurring event. Its data model is a month, day, and calendar.
• Temporal.PlainYearMonth represents a month in a specific year, eg January 2022. Its data model is a year, month, and calendar.
• Temporal.PlainTime represents a timezone-less time of day: a local time without reference to date, time zone, or calendar. Its data model is an hour/minute/second, with seconds resolution down to 9 decimal digits (nanoseconds).
• Temporal.PlainDateTime represents a local date and time without any reference to the time zone. Its data model is year/month/day/hour/minute/second and a calendar. This type is rarely used, because the types above cover most use cases. If you only care about the exact timestamp and don't care about time zones, then use Temporal.Instant . If you only care about the local date, then use Temporal.PlainDate . If you care about the exact time and the time zone, then use Temporal.ZonedDateTime . Other than the few use cases detailed in the Temporal.PlainDateTime documentation, most of the time it's better to use a different type.
• Temporal.Duration represents a period of time. Its data model is a number of years, months, days, hours, minutes, seconds, milliseconds, microseconds, and nanoseconds.
• Temporal.TimeZone represents an IANA time zone like Asia/Tokyo or (rarely) an offset time zone like +06:00 . Its data model is the canonical ID of the time zone, eg "Asia/Tokyo" or "+06:00" .
• Temporal.Calendar represents a calendar like Hebrew, Chinese, or the default ISO 8601 calendar. Its data model is the ID of the calendar, eg "iso8601" or "hebrew" .

Note that localized string formats like '12/25/2022' are not parseable by Temporal. Only unambiguous, computer-readable formats can be parsed by Temporal, like '2022-25-12' .