使用group_by starting_of_month，我如何获得一个活动以在下个月再次显示？

Question

Using Rails 5.0.2

I have a bunch of events, grouped by month that looks like this:

---

April

Event 1

23 April - 24 April

Event 2

28 April - 22 June

---

May

Event 3

4 May - 5 May

---

The problem is, some events go for ages! Eg Event 2 starts 23 April but finishes 22 June.

How would I get the event item to show up again in the next month(s)?

Current working code:

Controller:

@monthly = @events.group_by { |t| t.start_date.beginning_of_month }

Index view:

<% @monthly.sort.each do |month, event| %>
  <h2><%= month.strftime('%B') %></h2>

    <% for event in event %>

      <li><%= event.title %></li>
      <%= event.start_date %>
      <%= event.end_date %>

    <% end %>
<% end %>

Thanks ya'll!

Answer 1

One approach you could take is to first define the list of all months in the range to be displayed, and then associate all events with that month.

You may wish to tweak the code below for your needs - eg if you don't want to show events in the past, or in the next calendar year:

first_start_month = Event.minimum(:start_date).beginning_of_month
last_end_month = Event.maximum(:end_date).beginning_of_month

months = [first_start_date]
while(months.last != last_end_month) do
  months << months.last + 1.month
end

@monthly_events = months.map do |m|
  [m, @events.select { |e| (e.start_date .. e.end_date).include?(m) }]
end.to_h

With this, your view code can remain basically unchanged:

<% @monthly_events.each do |month, events| %>
  <h2><%= month.strftime('%B') %></h2>

    <% events.each do |event| %>

      <li><%= event.title %></li>
      <%= event.start_date %>
      <%= event.end_date %>

    <% end %>
<% end %>