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javascriptdateutc

set / get VS setUTC / getUTC

I'm working with dates and I was wondering if there was a border case where:

var d2 = new Date(d);
d.setHours(d.getHours() + n) !== d2.setUTCHours(d2.getUTCHours() + n)

..?

Solution

  • In the US this year (2016), Daylight Savings time starts at 2:00AM on Sunday 13 March:

    var dstDate = new Date(2016, 2, 13);
var dstUTC = new Date(dstDate);

    If we add 3 hours as per your question:

    dstDate.setHours(dstDate.getHours() + 3);
console.log(dstDate); // 3:00AM

dstUTC.setUTCHours(dstUTC.getUTCHours() + 3);
console.log(dstUTC); // 4:00 AM

    (My local time zone is UTC-6.)