Javascript 将日期和时间转换为 UTC
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Convert date and time to UTC
提问by erichardson30
I am asking the user to input a date and time into my application. The user will input a time based on the timezone they are in. When I save this date and time to my database I want to convert the time to UTC so that when I query by time (which is done in UTC) I can find the entries.
我要求用户在我的应用程序中输入日期和时间。用户将根据他们所在的时区输入时间。当我将此日期和时间保存到我的数据库时，我想将时间转换为 UTC，以便当我按时间查询（以 UTC 完成）时，我可以找到条目。
This is what I've currently done :
这是我目前所做的：
var date = new Date();
var dateString = "0" + (date.getMonth() + 1) + "/" + date.getDate() + "/" + date.getFullYear() + " " + time;
//format date
date = moment(dateString, "MM/DD/YYYY HH:mm a");
date = new Date(date).toISOString();
Where time is the time the user enters (ex if I want to schedule something for 11:00am, time = 11:00am)
time 是用户进入的时间（例如，如果我想在上午 11:00 安排某事，则时间 = 11:00 am）
When this is saved to the database, it looks like :
ISODate("2016-05-09T11:00:00Z")which is not correct since that is a EST saved as Zulu time.
当它保存到数据库时，它看起来像：
ISODate("2016-05-09T11:00:00Z")这是不正确的，因为这是保存为祖鲁时间的 EST。
How can I convert the time (I am using moment) to be saved as the correct Zulu time?
如何将时间（我正在使用时刻）转换为正确的祖鲁时间？
回答by WonderGrub
One option would be to use Javascript's built-in UTC functions.
一种选择是使用 Javascript 的内置 UTC 函数。
getUTCDate() - Returns the day of the month, according to universal time (from 1-31)
getUTCDay() - Returns the day of the week, according to universal time (from 0-6)
getUTCFullYear()- Returns the year, according to universal time
getUTCHours() - Returns the hour, according to universal time (from 0-23)
getUTCMilliseconds() - Returns the milliseconds, according to universal time (from 0-999)
getUTCMinutes() - Returns the minutes, according to universal time (from 0-59)
getUTCMonth() - Returns the month, according to universal time (from 0-11)
getUTCSeconds() - Returns the seconds, according to universal time (from 0-59)
For example,
例如，
new Date('2016-05-09 10:00:00')
returns Mon May 09 2016 10:00:00 GMT-0400
new Date('2016-05-09 10:00:00').getUTCHours()
returns 14
UPDATE: Examples (including .toISOString())
更新：示例（包括 .toISOString()）
If we choose July 4, 2016 @ 8:00 PM Eastern Time (GMT-0400), UTC would be July 5, 2016 @ 00:00 (midnight):
如果我们选择东部时间 2016 年 7 月 4 日晚上 8:00 (GMT-0400)，UTC 将是 2016 年 7 月 5 日 @ 00:00（午夜）：
var date = new Date('2016-07-04 20:00:00')
date.getUTCFullYear = 2016
date.getUTCMonth = 6 (0 base)
date.getUTCDate = 5
date.getUTCHours = 0
date.getUTCMinutes = 0
var date = new Date('2016-07-04 20:00:00')
date.toISOString() = "2016-07-05T00:00:00.000Z" (UTC)
回答by erichardson30
To fix this issue I used the moment-timezone library.
为了解决这个问题，我使用了 moment-timezone 库。
I first set the timezone on the server since it will only be accessed by EST :
我首先在服务器上设置时区，因为它只能由 EST 访问：
moment.tz.setDefault("America/New_York");
Then all I needed to do was set the timezone on the moment object to UTC by :
然后我需要做的就是通过以下方式将时刻对象上的时区设置为 UTC：
date = moment(dateString, "MM/DD/YYYY HH:mm a").tz("UTC");
This successfully converts the time from EST to UTC
这成功地将时间从 EST 转换为 UTC
