Dayjs: How to compare time is the same day

[Shuhua95]

like moment.js
moment().isSame(date, "day")

1. dayjs().diff(date, 'day') === 0
2. dayjs().format('YYYYMMDD') === dayjs(date).format('YYYYMMDD')

How to make an elegant comparison

dayjs().isSame(date, 'day')
It seems that second parameters are not supported?

[maeriens]

After digging a bit in the code, as the docs point that isSame() can receive only one argument but is not really that descriptive; I found out that it checks the Unix Timestamp of the dates compared by using .valueOf(); so unless you are that precise with the comparison, it will always be false.

In terms of elegance, the first one looks nicer; but I am using the second one as I came across a small issue with a false positive when using the full timestamp because it seems that .diff(date, 'day') checks that it's within the 24 hour range (not that I checked thoroughly, just hit that brickroad and added formatting).

It would be nice to expand a bit the isSame() method to help in this cases.

[Shuhua95]

@maeriens thx you comment 😘. I used it back moment.js, Avoid these problems 😞

[justin-schroeder]

Agreed, second argument should be supported to more closely conform to moment's api.

[probablyup]

I found out that it checks the Unix Timestamp of the dates

That's pretty different than what the documentation suggests:

https://github.com/iamkun/dayjs/blob/master/docs/en/API-reference.md#is-same-issamecompared-dayjs

Returns a boolean indicating whether the Dayjs's date is the same as the other supplied Dayjs's.

It seems that it should just be comparing the month day and year.

[suspectpart]

Please check ongoing discussion on Pull Request https://github.com/iamkun/dayjs/pull/404

[iamkun]

:tada: This is included in version 1.8.0 :tada:

The release is available on:

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

Your semantic-release bot :package::rocket: