Add next and previous day of week api to ActiveSupport

[iguchi1124]

Summary

I want a next day of week api on ActiveSupport datetime extentions.

So, I implemented next day of week api.

For example,

date = Date.new(2016, 9, 26)

date.monday? # => true
date.next_monday # => date + 1.week
date.next_tuesday # =>  date + 1.day

WDYT?

P.S.

The difference between next_week(:tuesday) and next_tuesday .

date = Date.today.monday
date.next_week(:tuesday) # == date + 8.days
date.next_tuesday # == date + 1.day

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[schneems]

Mostly active support is on lock down. So probably not cc/ @matthewd

[iguchi1124]

Thank you for reviewing !

Hmm...

I think this API has many usecases.

https://github.com/search?q=def+next_day_of_week&type=Code&utf8=%E2%9C%93

[pixeltrix]

@iguchi1124 this doesn't seem any different that using next_week? e.g:

>> date = Date.new(2016, 9, 26)
=> Mon, 26 Sep 2016 
>> date.next_week(:monday)
=> Mon, 03 Oct 2016 

We already have too many ways of doing things with dates and times that we have to keep fixing because we missed them (e.g. fixing alias of since to in in #26597). So I don't think this is a good idea, sorry.

[iguchi1124]

@pixeltrix

next_week is returns next week's day of week, but

this API returns "next day of week".

for example,

  def test_next_day_of_week
    datetime = DateTime.new(2016, 9, 24, 0, 30) # saturday 
    assert_equal datetime.next_monday, datetime.since(2.days)
    assert_equal datetime.next_tuesday, datetime.since(3.days)
    assert_equal datetime.next_wednesday, datetime.since(4.days)
    assert_equal datetime.next_thursday, datetime.since(5.days)
    assert_equal datetime.next_friday, datetime.since(6.days)
    assert_equal datetime.next_saturday, datetime.since(1.week)
    assert_equal datetime.next_sunday, datetime.since(1.day)
  end

[iguchi1124]

@pixeltrix

When I wanted to next tuesday and today is monday,

next_week(:tuesday) returns today + 1.day + 1.week,

but actually I want today + 1.day.

[pixeltrix]

@iguchi1124 I see the difference but the method names just don't work right. If some one came up to me in the street on a monday and said "I'll see you next tuesday" then I'd take it to mean the tuesday in the following week and not the day afterwards.

However I can see the need for getting the next occurrence of a particular day from an date/time instance so let me have a think about what the API should be.

[iguchi1124]

@pixeltrix

if the Date/Time instance is monday, I think "next_tuesday" of the Date/Time instance is actually means "this tuesday".

In other words, someone asks "When is the next tuesday of September 26th? " (It is monday) , The answer is September 27th. I think.

But, I don't understand completely that english speaker feel from these method names. 💭

[schneems]

Next Tuesday is ambiguous. It could mean the 27th or a week from the 27th. Some people think the 27th is " this Tuesday" because it is the only Tuesday in this week and others think it is "next Tuesday" because it is literally the next one. Given the confusion over the naming and the current general bloat of Active Support im voting we close this.

[pixeltrix]

@schneems I agree that names like next_monday are ambiguous so shouldn't be added but there is a gap as far as I can tell with getting the next or previous occurrence of a day of the week. In fact this did ring a bell and I managed to track down where I'd monkey patched Date to get this functionality in an app. This is what I did:

class Date
  def next_occur(day_of_week)
    target = (DAYS_INTO_WEEK.fetch(day_of_week) + 1) % 7
    days_since((target - wday - 1) % 7 + 1)
  end

  def prev_occur(day_of_week)
    target = (DAYS_INTO_WEEK.fetch(day_of_week) + 1) % 7
    days_since(-((wday - target + 6) % 7 + 1))
  end
  alias_method :last_occur, :prev_occur
end

(Tided up a bit for public consumption 😄 )

So while I agree that both the method names and implementation of this PR are not correct, the need for the API exists.

@rafaelfranca @jeremy wdyt?

[nynhex]

I also monkey patched this behavior for my own use case but I would agree that the method names are ambiguous and confusing for some but I'd also agree that the API should exist. But perhaps with an easier to read method nomenclature.

[iguchi1124]

Thank you for your reviews and comments !

I understood these naming is too ambiguous.

How about next_coming_tuesday and last_tuesday or next_occur_tuesday and prev_occur_tuesday ? (also other days of week)

[iguchi1124]

or next_occur(:tuesday) and prev_occur(:tuesday) same as using next_week method?

[iguchi1124]

@rafaelfranca @jeremy What do you think about this PR?

[iguchi1124]

@dhh what do you think about this PR?

[dhh]

I buy #next_occuring(weekday) and #prev_occurring(weekday) (don't like the occur abbreviation) 👍

[iguchi1124]

Thank you for reviews. I 'll fix this method name soon!

[matthewd]

next_occurring(:tuesday) is definitely nicer than tomorrow.end_of_week(:wednesday), which I've previously used.

@iguchi1124 note that's public next_occurring/prev_occurring methods: no per-day extras.

[iguchi1124]

I fixed this pull request. please review 🙏 @dhh @matthewd

[iguchi1124]

ooops

[rafaelfranca]

Could you squash your commits?

[iguchi1124]

squashed.

[dhh]

❤️