在Javascript中计算UTC日期和给定日期之间的时间差

Question

在 Javascript 中，我想计算今天的日期（但已调整为 GMT0）与给定日期 1970/01/01 之间的差异（以毫秒为单位）。

例如在 powershell 上，这将是 (([datetime]::UtcNow) - (get-date "1/1/1970")).TotalMilliseconds

我尝试像这样使用 moment.js：

A = moment.utc();
B = moment('19700101', 'YYYYMMDD')

console.log("A is ",A)
console.log("B is ",B)

console.log("A format is ", A.format())
console.log("B format is ", B.format())

console.log("Milisec diff : ", A.diff(B,'miliseconds'))

返回

A is  h {_isAMomentObject: true, _useUTC: true, _isUTC: true, _l: undefined, _i: undefined, …}_d: Fri Nov 05 2021 10:43:43 GMT+0100 (heure normale d’Europe centrale) {}_f: undefined_i: undefined_isAMomentObject: true_isUTC: true_isValid: true_l: undefined_offset: 0_pf: {empty: false, unusedTokens: Array(0), unusedInput: Array(0), overflow: -2, charsLeftOver: 0, …}_strict: undefined_useUTC: true_z: null[[Prototype]]: Object

B is  h {_isAMomentObject: true, _i: '19700101', _f: 'YYYYMMDD', _l: undefined, _strict: undefined, …}_a: (7) [1970, 0, 1, 0, 0, 0, 0]_d: Thu Jan 01 1970 00:00:00 GMT+0100 (heure normale d’Europe centrale) {}_f: "YYYYMMDD"_i: "19700101"_isAMomentObject: true_isUTC: false_isValid: true_l: undefined_pf: {empty: false, unusedTokens: Array(0), unusedInput: Array(0), overflow: -1, charsLeftOver: 0, …}_strict: undefined[[Prototype]]: Object

A format is  2021-11-05T09:43:43+00:00
B format is  1970-01-01T00:00:00+01:00
Milisec diff :  1636109023628

所以差异不是很好，它需要 A 与当地时间（对我来说是 10:43）而不是 UTC 时间（9:43）。这可能是因为您必须考虑 A.format 才能看到 9:43，但我们不能将 A.format 赋予 diff 函数。

感谢您的帮助！

Answer 1

对上面的代码稍加改动应该会得到你想要的结果：

A = moment.utc();
B = moment.utc(0)

console.log("A is ",A)
console.log("B is ",B)

console.log("A format is ", A.format())
console.log("B format is ", B.format())

console.log("Milisec diff : ", A.diff(B,'miliseconds'))

.as-console-wrapper { max-height: 100% !important; top: 0; }

<script src="https://cdnjs.cloudflare.com/ajax/libs/moment.js/2.29.1/moment.min.js" integrity="sha512-qTXRIMyZIFb8iQcfjXWCO8+M5Tbc38Qi5WzdPOYZHIlZpzBHG3L3by84BBBOiRGiEb7KKtAOAs5qYdUiZiQNNQ==" crossorigin="anonymous" referrerpolicy="no-referrer"></script>

您还可以使用带有 UTC 时区 ('Z') 的 ISO 8601 时间戳，如下所示：

A = moment.utc();
B = moment('1970-01-01T00:00:00Z')

console.log("A is ",A)
console.log("B is ",B)

console.log("A format is ", A.format())
console.log("B format is ", B.format())

console.log("Milisec diff : ", A.diff(B,'miliseconds'))

.as-console-wrapper { max-height: 100% !important; top: 0; }

<script src="https://cdnjs.cloudflare.com/ajax/libs/moment.js/2.29.1/moment.min.js" integrity="sha512-qTXRIMyZIFb8iQcfjXWCO8+M5Tbc38Qi5WzdPOYZHIlZpzBHG3L3by84BBBOiRGiEb7KKtAOAs5qYdUiZiQNNQ==" crossorigin="anonymous" referrerpolicy="no-referrer"></script>

使用原生 JS 日期对象的更简单方法是简单地使用 Date.now()，这将为您提供自 1970-01-01 00:00:00 UTC 以来的毫秒数。

console.log("Milisec diff : ", Date.now())