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Refactor OADate handling

This commit is contained in:
Ivan Trusov 2022-06-02 13:28:52 +03:00
parent 51d05ad8a0
commit b1c5037ca8
1 changed files with 11 additions and 13 deletions
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xlsx.js generated
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@ -3213,23 +3213,21 @@ function evert_arr(obj) {
return o;
}
var basedate = new Date(Date.UTC(1899, 11, 30, 0, 0, 0)); // 2209161600000
var base1900 = Date.UTC(1899, 11, 30);
var base1904 = Date.UTC(1904, 0, 1);
// According to https://docs.microsoft.com/ru-ru/archive/blogs/ericlippert/erics-complete-guide-to-vt_date
// we must treat OLE Automation Date as it has no timezone at all.
// So to avoid any possible TZ/DST issues do calculations in UTC
function datenum(v, date1904) {
var epoch = v.getTime();
if(date1904) epoch -= 1462*24*60*60*1000;
var dnthresh = basedate.getTime() + v.getTimezoneOffset() * 60000;
return (epoch - dnthresh) / (24 * 60 * 60 * 1000);
var start = date1904 ? base1904 : base1900;
var vTime = Date.UTC(v.getFullYear(), v.getMonth(), v.getDate(), v.getHours(), v.getMinutes(), v.getSeconds(), v.getMilliseconds());
return (vTime - start) / 86400000;
}
var refdate = new Date();
var refoffset = refdate.getTimezoneOffset();
var dnthresh = basedate.getTime() + refoffset * 60000;
function numdate(v) {
var out = new Date();
out.setTime(v * 24 * 60 * 60 * 1000 + dnthresh);
if (out.getTimezoneOffset() !== refoffset) {
out.setTime(out.getTime() + (out.getTimezoneOffset() - refoffset) * 60000);
}
var out = new Date(base1900 + v * 86400000);
// De-adjust timezone offset
out.setTime(out.getTime() + out.getTimezoneOffset() * 60000);
return out;
}