如何使用 Moment 在 React-Native 中将 Firestore 时间戳 UTC 转换为 UTC+1？

Question

I want to use MomentJs to convert Firestore Timestamp (which is by Default UTC) to UTC+1. How can I do that?

firestore.Timestamp.now().toDate()

PS I dont want to use the local/device's time.

Answer 1

Firestore Timestamp (which is by Default UTC)

There is no "default" really. When you have a Timestamp object (or a JavaScript Date , or any other native date object from a modern operating system), the moment in time is always represented internally in UTC.

When you call toDate() on a timestamp, the resulting Date is still internally represented in UTC.

Don't be confused about the "default" string representation of a Date object. It will appear in the local timezone where the computer's operation system is configured. But internally, it's still UTC.

If you want to format the timestamp as a string for another timezone, you can certainly do that. momentjs has an accompanying library Moment Timezone that can help you with that. The momentjs library itself will not help you with timezones (other than the one provided by the local of the system where it is running), as it's generally understood that native timestamps are always UTC.