Adding days across daylight savings does not work as expected

Describe the bug I’m seeing a weird issue with using add() along with utc() across a daylight savings boundary where it doesn’t add a full day.

Expected behavior Given the following code:

var dayjs = require('dayjs');
var utc = require('dayjs/plugin/utc');
dayjs.extend(utc);

let testDate = dayjs('2019-03-10')
  .utc()
  .startOf('day');
console.log('TESTDATE: ', testDate.format());
let testDate2 = testDate.add(1, 'day');
console.log('TESTDATE2:', testDate2.format());

I expect it to output the following:

TESTDATE:  2019-03-10T00:00:00Z
TESTDATE2: 2019-03-11T00:00:00Z

Instead I see this:

TESTDATE:  2019-03-10T00:00:00Z
TESTDATE2: 2019-03-10T23:00:00Z

Replication here: https://runkit.com/accelerate/runkit-dayjs-daylight-savings

NOTE: I tested the same code with MomentJS and do get the expected behavior.

Information

• Day.js: 1.8.13
• OS: MacOS 10.14.4
• Chrome: 74.0.3729.108

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IssueHunt Summary

iamkun has been rewarded.

Backers (Total: $100.00)

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Submitted pull Requests

• #590 fix: Fix UTC plugin add day DST bug

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[iamkun]

🎉 This issue has been resolved in version 1.8.14 🎉

The release is available on:

• npm package (@latest dist-tag)
• GitHub release

Your semantic-release bot 📦🚀

[issuehunt-app[bot]]

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