在UTC中将UTC字符串转换为时代 [英] Converting UTC string to epoch time in javascript

问题描述

如何在UTC中将UTC日期时间字符串（例如 2011-03-29 17:06:21 UTC ）转换为Epoch（毫秒）？

How can I convert UTC date-time string (e.g. 2011-03-29 17:06:21 UTC) into Epoch (milliseconds) in javascript?

如果这是不可能的，是否有任何方式来比较（如<，）UTC日期时间字符串？

If this is not possible, is there any way to compare (like <, >) UTC date time strings?

推荐答案

请注意，UTC日期字符串可以按字典顺序比较，如字符串，因为较高的顺序值在字符串中最左边。

Note that UTC date strings can be compared lexicographically, like strings, since the higher order values appear leftmost in the string.

var s1 = '2011-03-29 17:06:21 UTC'
  , s2 = '2001-09-09 01:46:40 UTC';
s1 > s2; // => true
s2 > s1; // => false

您可以从示例字符串中提取日期字段，并使用< a href =https://developer.mozilla.org/en/JavaScript/Reference/Global_Objects/Date/UTC =nofollow> Date.UTC 方法：

You can extract the date fields from your example string and return the number of milliseconds by using the Date.UTC method:

var getEpochMillis = function(dateStr) {
  var r = /^\s*(\d{4})-(\d\d)-(\d\d)\s+(\d\d):(\d\d):(\d\d)\s+UTC\s*$/
    , m = (""+dateStr).match(r);
  return (m) ? Date.UTC(m[1], m[2]-1, m[3], m[4], m[5], m[6]) : undefined;
};
getEpochMillis('2011-03-29 17:06:21 UTC'); // => 1301418381000
getEpochMillis('2001-09-09 01:46:40 UTC'); // => 1000000000000

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