問題描述
問題是我使用的是這樣的代碼:
Well the problem is that I was using code like this:
new Date().toJSON().slice(0, 10)
將我的日期作為 YYYY-MM-DD 字符串，然后我在一些 mysql 查詢和一些條件語句中使用它作為參數.在一天結束時，我沒有得到正確的日期，因為它仍然在前一天(我的時區偏移量是 +2/3 小時).
to get my date as YYYY-MM-DD string, then I use it like parameter in some mysql queries and in some condition statements. In the end of the day I wasn't getting the right date since it was still in the previous day (my timezone offset is +2/3 hours).
我沒有注意到 toJSON 方法沒有考慮到您的時區偏移，所以我最終得到了這個 hacky 解決方案:
I haven't noticed that the toJSON method does not take into account your timezone offset, so I've ended up with this hacky solution:
var today = new Date();
today.setHours( today.getHours()+(today.getTimezoneOffset()/-60) );
console.log(today.toJSON().slice(0, 10));
有沒有更優雅的解決方案?
Is there a more elegant solution?
- 這里是測試代碼:http://jsfiddle.net/simo/qwhYw/
- JavaScript toJSON 方法
- JavaScript 日期對象
推薦答案
ECMAScript 中的日期對象在內部是 UTC.時區偏移量用于當地時間.
Date objects in ECMAScript are internally UTC. The timezone offset is used for local times.
Date.prototype.toJSON 的規范說它使用 Date.prototype.toISOString，表示時區始終為 UTC".您的解決方案正在做的是將日期對象的 UTC 時間值偏移時區偏移量.
The specification for Date.prototype.toJSON says that it uses Date.prototype.toISOString, which states that "the timezone is always UTC". What your solution is doing is offsetting the UTC time value of the date object by the timezone offset.
考慮將您自己的方法添加到 Date.prototype，例如
Consider adding your own method to Date.prototype, e.g.
Date.prototype.toJSONLocal = function() {
function addZ(n) {
return (n<10? '0' : '') + n;
}
return this.getFullYear() + '-' +
addZ(this.getMonth() + 1) + '-' +
addZ(this.getDate());
}
編輯
如果你想擠出額外的性能，以下應該更快:
Edit
If you want to squeeze extra performance, the following should be faster:
Date.prototype.toJSONLocal = (function() {
function addZ(n) {
return (n<10? '0' : '') + n;
}
return function() {
return this.getFullYear() + '-' +
addZ(this.getMonth() + 1) + '-' +
addZ(this.getDate());
};
}())
但這有點過早優化的味道，所以除非你在很短的時間內調用它數千次，否則我不會打擾.
But that smacks of premature optimisation, so unless you are calling it thousands of times in a very short period, I wouldn't bother.
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