使用Javascript获取特定日期的纪元

Question

如何07/26/2010使用Javascript 转换为UNIX时间戳？

Answer 1

您可以创建一个Date对象,并对其进行调用getTime:

new Date(2010, 6, 26).getTime() / 1000

Answer 2

new Date("2016-3-17").valueOf() 

将回归一个漫长的时代

Answer 3

一些答案没有解释 JavaScript Date 对象时区变化的副作用。因此，如果这对您来说是个问题，您应该考虑这个答案。

方法 1：取决于机器的时区

默认情况下，JavaScript 会根据机器的时区返回 Date，因此getTime()结果因计算机而异。您可以检查此行为运行：

new Date(1970, 0, 1, 0, 0, 0, 0).getTime()
    // Since 1970-01-01 is Epoch, you may expect ZERO
    // but in fact the result varies based on computer's timezone

如果考虑到您的时区，您真的想要自 Epoch 以来的时间，这不是问题。因此，如果您想获取自 Epoch 以来当前日期的时间，甚至是基于计算机时区的指定日期，您可以继续使用此方法。

// Seconds since Epoch (Unix timestamp format)

new Date().getTime() / 1000             // local Date/Time since Epoch in seconds
new Date(2020, 11, 1).getTime() / 1000  // time since Epoch to 2020-12-01 00:00 (local timezone) in seconds

// Milliseconds since Epoch (used by some systems, eg. JavaScript itself)

new Date().getTime()                    // local Date/Time since Epoch in milliseconds
new Date(2020,  0, 2).getTime()         // time since Epoch to 2020-01-02 00:00 (local timezone) in milliseconds

// **Warning**: notice that MONTHS in JavaScript Dates starts in zero (0 = January, 11 = December)

方法 2：机器的时区无关

但是，如果您想摆脱时区的变化并获取自 Epoch 以来指定日期的 UTC 时间（即，时区无关），您需要使用Date.UTC方法或将日期从您的时区转换为 UTC：

Date.UTC(1970,  0, 1)
    // should be ZERO in any computer, since it is ZERO the difference from Epoch

    // Alternatively (if, for some reason, you do not want Date.UTC)
    const timezone_diff = new Date(1970, 0, 1).getTime()  // difference in milliseconds between your timezone and UTC
    (new Date(1970,  0, 1).getTime() - timezone_diff)
    // should be ZERO in any computer, since it is ZERO the difference from Epoch

因此，使用此方法（或者，减去差异），结果应该是：

// Seconds since Epoch (Unix timestamp format)

Date.UTC(2020,  0, 1) / 1000  // time since Epoch to 2020-01-01 00:00 UTC in seconds

    // Alternatively (if, for some reason, you do not want Date.UTC)
    const timezone_diff = new Date(1970, 0, 1).getTime()
    (new Date(2020,  0, 1).getTime() - timezone_diff) / 1000  // time since Epoch to 2020-01-01 00:00 UTC in seconds
    (new Date(2020, 11, 1).getTime() - timezone_diff) / 1000  // time since Epoch to 2020-12-01 00:00 UTC in seconds

// Milliseconds since Epoch (used by some systems, eg. JavaScript itself)

Date.UTC(2020,  0, 2)   // time since Epoch to 2020-01-02 00:00 UTC in milliseconds

    // Alternatively (if, for some reason, you do not want Date.UTC)
    const timezone_diff = new Date(1970, 0, 1).getTime()
    (new Date(2020,  0, 2).getTime() - timezone_diff)         // time since Epoch to 2020-01-02 00:00 UTC in milliseconds

// **Warning**: notice that MONTHS in JavaScript Dates starts in zero (0 = January, 11 = December)

IMO，除非您知道自己在做什么（请参阅上面的注释），否则您应该更喜欢Method 2，因为它与机器无关。

尾注

尽管此答案中的建议，并且由于Date.UTC没有指定的日期/时间就不起作用，您可能倾向于使用替代方法并执行以下操作：

const timezone_diff = new Date(1970, 0, 1).getTime()
(new Date().getTime() - timezone_diff)  // <-- !!! new Date() without arguments
    // means "local Date/Time subtracted by timezone since Epoch" (?)

这没有任何意义，而且可能是错误的（您正在修改日期）。请注意不要这样做。如果您想从当前日期AND TIME获取自 Epoch 以来的时间，您很可能可以使用方法 1。

Answer 4

请查看http://www.w3schools.com/jsref/jsref_obj_date.asp

有一个函数UTC()返回unix时代的毫秒数.

Answer 5

Date.parse()方法解析日期的字符串表示形式，并返回自 以来的毫秒数January 1, 1970, 00:00:00 UTC。

const unixTimeZero = Date.parse('01 Jan 1970 00:00:00 GMT');
const javaScriptRelease = Date.parse('04 Dec 1995 00:12:00 GMT');

console.log(unixTimeZero);
// expected output: 0

console.log(javaScriptRelease);
// expected output: 818035920000

探索更多信息：Date.parse()