guisturdy / dayjs-plugin-utc

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this is a plugin for dayjs, that gives dayjs the ability to operate UTC timezone

Usage

• Via NPM:

npm i dayjs-plugin-utc --save

import dayjsPluginUTC from 'dayjs-plugin-utc'

dayjs.extend(dayjsPluginUTC)

• Via CDN:

<!-- Latest compiled and minified JavaScript -->
<script src="https://unpkg.com/dayjs"></script>
<script src="https://unpkg.com/dayjs-plugin-utc"></script>
<script>
  dayjs.extend(dayjsPluginUTC.default)
</script>

⚠️ NOTICE⚠️

when NOT add this plugin dayjs() will return an instance that timezone based of you local

dayjs('2018-05-18T03:04:05+06:00').format() // 2018-05-18T05:04:05+08:00

after load this plugin the timezone of instance return by dayjs() will rely on what you passed

dayjs.extend(dayjsPluginUTC)
dayjs('2018-05-18T03:04:05+06:00').format() // 2018-05-18T03:04:05+06:00

if you always want an local timezone instance would be create or you already use dayjs in you project

you can load this plugin with option parseToLocal: true

dayjs.extend(dayjsPluginUTC, { parseToLocal: true })
dayjs('2018-05-18T03:04:05+06:00').format() // 2018-05-18T05:04:05+08:00

API

Parse

get an instance in UTC

  dayjs.utc() 
  dayjs.utc('2018-05-18T03:04:05+06:00') 
  /* (string | number | Date | Dayjs) support like dayjs() */

Get

with dayjs().utcOffset() you can get the UTC offset in minutes.

Note: dayjs().utcOffset() returns the real offset from UTC, not the reverse offset (as returned by Date.prototype.getTimezoneOffset).

also you can check the timezone of an instance is local or UTC by dayjs().isLocal() and dayjs().isUTC()

  dayjs().utcOffset() // (-480, -120, 0, 120, 480, etc.)
  dayjs().isLocal()   // true
  dayjs().isUTC()     // false

Set

using dayjs().utc() and dayjs().local() you can set the timezone to UTC or you local timezone , and dayjs().utcOffset(Number) you can specify the timezone you want

  let day = dayjs('2018-05-18T03:04:05+06:00')
  
  day.utc().format()           // 2018-05-17T21:04:05+00:00

  day.local().format()         // 2018-05-18T05:04:05+08:00

  day.utcOffset(240).format()  // 2018-05-18T01:04:05+04:00