Question

Now I’m trying to make helper method like this.
How can I compare the datetime of argument with Today’s date?

def todate_datetime(date_time)
    date_time = Date.today ? "<font color='red'>#{date_time}</font>" : date_time
end

UPDATE:

view

<%= today_datetime(community_topic.updated_at) %>

helpers

def today_datetime(date_time)
  date_time == Date.today ? "<font color='red'>#{date_time.to_s(:ct)}</font>" : date_time.to_s(:ct)
end

Answer 1

Starting from ruby 1.9.2 you can directly compare a DateTime object with a Date object in ruby, e.g. try in irb:

require 'date'
today = DateTime.new(2013,1,4)
 => #<DateTime: 2013-01-04T00:00:00+00:00 ((2456297j,0s,0n),+0s,2299161j)> 
today == Date.today
=> true

However, Rails has its own DateTime object (APIdock Rails DateTime). One option is to convert the Rails Object to a date via the to_date method

So then the helper method could look like this:

def todate_datetime(date_time)
  date_time.to_date == Date.today ? "<font color='red'>#{date_time}</font>" : date_time
end

EDIT: it might be more accurate to compare the date_time argument to DateTime.current.to_date since that takes the config.time_zone into account if set:

def todate_datetime(date_time)
  date_time.to_date == DateTime.current.to_date ? "<font color='red'>#{date_time}</font>" : date_time
end