如何使用 moment-timezone 将 localTimeString 转换为 utcTimeString 并返回 localTimeString

Question

当我的应用程序中有人选择日期和时间并且我想以 UTC 时间存储该 DateTime 时，如何将存储的 DateTime 转换回用户的本地时区？

const moment = require('moment-timezone') 
const myTimeZone = 'Europe/Copenhagen'
const nowUTC = moment.utc().format('YYYY-MM-DD HH:mm')

const someDanishTime = '2019-04-19 17:00'

const someDanishTimeAsUTC = moment.tz(someDanishTime,myTimeZone)
  .utc()
  .format('YYYY-MM-DD HH:mm') // returns 2019-04-19 15:00

const utcTimeAsSomeDanishTime = moment.tz(someDanishTimeAsUTC, myTimeZone)
  .format('YYYY-MM-DD HH:mm') // returns 2019-04-19 15:00

// I need a way to transform someDanishTimeAsUTC back to someDanishTime

Answer 1

您可以使用 moment.utc 将您的输入解析为 UTC

By default, moment parses and displays in local time.

If you want to parse or display a moment in UTC, you can use moment.utc() instead of moment().

然后你可以使用tz()函数将其转换为给定区域

The moment#tz mutator will change the time zone and update the offset.

这是一个活生生的例子：

const myTimeZone = 'Europe/Copenhagen'
const nowUTC = moment.utc().format('YYYY-MM-DD HH:mm')

const someDanishTime = '2019-04-19 17:00'

const someDanishTimeAsUTC = moment.tz(someDanishTime, myTimeZone)
  .utc()
  .format('YYYY-MM-DD HH:mm') // returns 2019-04-19 15:00

const utcTimeAsSomeDanishTime = moment.utc(someDanishTimeAsUTC).tz(myTimeZone)
  .format('YYYY-MM-DD HH:mm') // returns 2019-04-19 17:00
  
console.log(someDanishTimeAsUTC);
console.log(utcTimeAsSomeDanishTime);

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如何使用 moment-timezone 将 localTimeString 转换为 utcTimeString 并返回 localTimeString

How to transform a localTimeString to utcTimeString and back to localTimeString using moment-timezone

momentjs

moment-timezone