用moment（）更新时间偏移量.utcOffset（） [英] Updating time offset with moment().utcOffset()

问题描述

我在尝试使用 moment.js 处理时间偏移时遇到了一些问题。

I'm facing some issue trying to use moment.js for dealing with time offsets.

I在隐藏的输入中收集本地用户时间偏移：

I collect in an hidden input the local user time offset:

<script type="text/javascript">
  $(document).ready(function () { 
    $('input#timeoffset').val(moment().utcOffset()); 
  });
</script>

偏移量得到正确存储（在我的情况下，其值为-240）。稍后在服务器端（在utc时间运行）我尝试更新一些db存储的utcDate做类似的事情：

The offset gets correctly stored (in my case its value is -240). Later on the server side (which runs in utc time) I try to update some db stored utcDate doing something like:

var userDate = moment(utcDate).utcOffset(offset)

我的问题如下：
if我按上述方式运行我的代码我没有效果：

My issue is the following: if I run my code as above described I get no effects:

• utcDate：20151001 012421 +0000


• userDate：20151001 012421 +0000

• utcDate: 20151001 012421 +0000
• userDate: 20151001 012421 +0000

如果我翻转偏移标志我得到：

If I flip the offset sign I get:

• utcDate：20151001 012421 +0000


• userDate：20151001 052421 +0400

• utcDate: 20151001 012421 +0000
• userDate: 20151001 052421 +0400

我显然做错了（即使我的期望是第一个版本是正确的），你有任何提示吗？

I'm clearly doing something wrong (even if my expectation was that the first version was correct), do you have any hint?

在客户端，我在服务器端使用moment.js v2.10.6 moment-timezone.js v0.4.0和moment.js v2.10.6

On client-side I'm using moment.js v2.10.6 while on the server-side moment-timezone.js v0.4.0 and moment.js v2.10.6

推荐答案

主要问题是您将偏移量作为字符串而不是数字传递。

The main issue is that you are passing the offset as a string instead of a number.

moment.utc("2015-10-01 01:24:21").utcOffset("-240").format('YYYYMMDD HHmmss ZZ')
// "20151001 012421 +0000"

moment.utc("2015-10-01 01:24:21").utcOffset(-240).format('YYYYMMDD HHmmss ZZ')
// "20150930 212421 -0400"

如果您有以分钟为单位的偏移量，则必须使用数字形式。您可以随时转换它：

When you have an offset in terms of minutes, then you must use the numeric form. You can always convert it:

moment.utc("2015-10-01 01:24:21").utcOffset(+"-240").format('YYYYMMDD HHmmss ZZ')
// "20150930 212421 -0400"

Moment允许将偏移量作为字符串传递，但它希望它们采用ISO8601格式之一： [+/-] HH：mm 或 [+/-] HHmm 。

Moment does allow for offsets to be passed as strings, but it expects them to be in one of the ISO8601 formats: either [+/-]HH:mm or [+/-]HHmm.

moment.utc("2015-10-01 01:24:21").utcOffset("-04:00").format('YYYYMMDD HHmmss ZZ')
// "20150930 212421 -0400"

另外，请注意我使用 moment.utc（...）解析输入字符串。您刚刚使用时刻（...），这将使用本地时区，除非时区是明确的或者您传递日期对象而不是字符串。它还会在本地模式中保留时刻对象，因此除非时区，否则您的 utcDate 输出将是错误的该机器的实际设置为UTC。

Additionally, note that I used moment.utc(...) to parse the input string. You just used moment(...) which will use the local time zone unless the time zone is explicit or if you pass a Date object instead of a string. It will also leave the moment object in "local mode", so your utcDate output would be wrong unless the time zone of the machine was actually set to UTC.

最后，不要忘记时区！=偏移。您不能假设您获得的偏移对所有日期都有效。如果您需要将日期投影到用户的时区，您必须实际知道时区，例如 America / New_York 。你可以将它们与moment-timezone插件一起使用。

Lastly, don't forget "Time Zone != Offset". You can't assume that the offset you obtained is valid for all dates. If you need to project a date to to the user's time zone, you have to actually know the time zone, such as America/New_York. You can use these with the moment-timezone plugin.

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