implements weeks_ago and prev_week for Date/DateTime/Time [#5122 state:committed]

activesupport/CHANGELOG

 *Rails 3.1.0 (unreleased)*
 
+* Added weeks_ago and prev_week to Date/DateTime/Time. [Rob Zolkos, fxn]
+
 * Added before_remove_const callback to ActiveSupport::Dependencies.remove_unloadable_constants! [Andrew White]
 
 

activesupport/lib/active_support/core_ext/date/calculations.rb

@@ -5,6 +5,8 @@
 require 'active_support/core_ext/time/zones'
 
 class Date
+  DAYS_INTO_WEEK = { :monday => 0, :tuesday => 1, :wednesday => 2, :thursday => 3, :friday => 4, :saturday => 5, :sunday => 6 }
+
   if RUBY_VERSION < '1.9'
     undef :>>
 
@@ -127,6 +129,11 @@ def change(options)
     )
   end
 
+  # Returns a new Date/DateTime representing the time a number of specified weeks ago.
+  def weeks_ago(weeks)
+    advance(:weeks => -weeks)
+  end
+
   # Returns a new Date/DateTime representing the time a number of specified months ago.
   def months_ago(months)
     advance(:months => -months)
@@ -185,10 +192,15 @@ def end_of_week
   alias :sunday :end_of_week
   alias :at_end_of_week :end_of_week
 
+  # Returns a new Date/DateTime representing the start of the given day in the previous week (default is Monday).
+  def prev_week(day = :monday)
+    result = (self - 7).beginning_of_week + DAYS_INTO_WEEK[day]
+    self.acts_like?(:time) ? result.change(:hour => 0) : result
+  end
+
   # Returns a new Date/DateTime representing the start of the given day in next week (default is Monday).
   def next_week(day = :monday)
-    days_into_week = { :monday => 0, :tuesday => 1, :wednesday => 2, :thursday => 3, :friday => 4, :saturday => 5, :sunday => 6}
-    result = (self + 7).beginning_of_week + days_into_week[day]
+    result = (self + 7).beginning_of_week + DAYS_INTO_WEEK[day]
     self.acts_like?(:time) ? result.change(:hour => 0) : result
   end
 

activesupport/lib/active_support/core_ext/time/calculations.rb

@@ -22,7 +22,7 @@ def days_in_month(month, year = now.year)
 
     # Returns a new Time if requested year can be accommodated by Ruby's Time class
     # (i.e., if year is within either 1970..2038 or 1902..2038, depending on system architecture);
-    # otherwise returns a DateTime
+    # otherwise returns a DateTime.
     def time_with_datetime_fallback(utc_or_local, year, month=1, day=1, hour=0, min=0, sec=0, usec=0)
       time = ::Time.send(utc_or_local, year, month, day, hour, min, sec, usec)
       # This check is needed because Time.utc(y) returns a time object in the 2000s for 0 <= y <= 138.
@@ -117,6 +117,11 @@ def since(seconds)
   end
   alias :in :since
 
+  # Returns a new Time representing the time a number of specified weeks ago.
+  def weeks_ago(weeks)
+    advance(:weeks => -weeks)
+  end
+
   # Returns a new Time representing the time a number of specified months ago
   def months_ago(months)
     advance(:months => -months)
@@ -172,6 +177,11 @@ def end_of_week
   end
   alias :at_end_of_week :end_of_week
 
+  # Returns a new Time representing the start of the given day in the previous week (default is Monday).
+  def prev_week(day = :monday)
+    ago(1.week).beginning_of_week.since(DAYS_INTO_WEEK[day].day).change(:hour => 0)
+  end
+
   # Returns a new Time representing the start of the given day in next week (default is Monday).
   def next_week(day = :monday)
     since(1.week).beginning_of_week.since(DAYS_INTO_WEEK[day].day).change(:hour => 0)

activesupport/test/core_ext/date_ext_test.rb

@@ -110,6 +110,14 @@ def test_beginning_of_year
     assert_equal Date.new(2005,1,1).to_s, Date.new(2005,2,22).beginning_of_year.to_s
   end
 
+  def test_weeks_ago
+    assert_equal Date.new(2005,5,10), Date.new(2005,5,17).weeks_ago(1)
+    assert_equal Date.new(2005,5,10), Date.new(2005,5,24).weeks_ago(2)
+    assert_equal Date.new(2005,5,10), Date.new(2005,5,31).weeks_ago(3)
+    assert_equal Date.new(2005,5,10), Date.new(2005,6,7).weeks_ago(4)
+    assert_equal Date.new(2006,12,31), Date.new(2007,2,4).weeks_ago(5)
+  end
+
   def test_months_ago
     assert_equal Date.new(2005,5,5),  Date.new(2005,6,5).months_ago(1)
     assert_equal Date.new(2004,11,5), Date.new(2005,6,5).months_ago(7)
@@ -219,6 +227,14 @@ def test_advance_in_calendar_reform
     end
   end
 
+  def test_prev_week
+    assert_equal Date.new(2005,5,9), Date.new(2005,5,17).prev_week
+    assert_equal Date.new(2006,12,25), Date.new(2007,1,7).prev_week
+    assert_equal Date.new(2010,2,12), Date.new(2010,2,19).prev_week(:friday)
+    assert_equal Date.new(2010,2,13), Date.new(2010,2,19).prev_week(:saturday)
+    assert_equal Date.new(2010,2,27), Date.new(2010,3,4).prev_week(:saturday)
+  end
+
   def test_next_week
     assert_equal Date.new(2005,2,28), Date.new(2005,2,22).next_week
     assert_equal Date.new(2005,3,4), Date.new(2005,2,22).next_week(:friday)

activesupport/test/core_ext/date_time_ext_test.rb

@@ -92,6 +92,14 @@ def test_beginning_of_year
     assert_equal DateTime.civil(2005,1,1,0,0,0), DateTime.civil(2005,2,22,10,10,10).beginning_of_year
   end
 
+  def test_weeks_ago
+    assert_equal DateTime.civil(2005,5,29,10),  DateTime.civil(2005,6,5,10,0,0).weeks_ago(1)
+    assert_equal DateTime.civil(2005,5,1,10), DateTime.civil(2005,6,5,10,0,0).weeks_ago(5)
+    assert_equal DateTime.civil(2005,4,24,10), DateTime.civil(2005,6,5,10,0,0).weeks_ago(6)
+    assert_equal DateTime.civil(2005,2,27,10),  DateTime.civil(2005,6,5,10,0,0).weeks_ago(14)
+    assert_equal DateTime.civil(2004,12,25,10),  DateTime.civil(2005,1,1,10,0,0).weeks_ago(1)    
+  end
+
   def test_months_ago
     assert_equal DateTime.civil(2005,5,5,10),  DateTime.civil(2005,6,5,10,0,0).months_ago(1)
     assert_equal DateTime.civil(2004,11,5,10), DateTime.civil(2005,6,5,10,0,0).months_ago(7)
@@ -196,6 +204,14 @@ def test_advanced_processes_first_the_date_deltas_and_then_the_time_deltas
     assert_equal DateTime.civil(2010, 3, 29), DateTime.civil(2010, 2, 28, 22, 58, 59).advance(:months => 1, :hours => 1, :minutes => 1, :seconds => 1)
   end
 
+  def test_prev_week
+    assert_equal DateTime.civil(2005,2,21), DateTime.civil(2005,3,1,15,15,10).prev_week
+    assert_equal DateTime.civil(2005,2,22), DateTime.civil(2005,3,1,15,15,10).prev_week(:tuesday)
+    assert_equal DateTime.civil(2005,2,25), DateTime.civil(2005,3,1,15,15,10).prev_week(:friday)
+    assert_equal DateTime.civil(2006,10,30), DateTime.civil(2006,11,6,0,0,0).prev_week
+    assert_equal DateTime.civil(2006,11,15), DateTime.civil(2006,11,23,0,0,0).prev_week(:wednesday)
+  end
+
   def test_next_week
     assert_equal DateTime.civil(2005,2,28), DateTime.civil(2005,2,22,15,15,10).next_week
     assert_equal DateTime.civil(2005,3,4), DateTime.civil(2005,2,22,15,15,10).next_week(:friday)

activesupport/test/core_ext/time_ext_test.rb

@@ -130,6 +130,14 @@ def test_beginning_of_year
     assert_equal Time.local(2005,1,1,0,0,0), Time.local(2005,2,22,10,10,10).beginning_of_year
   end
 
+  def test_weeks_ago
+    assert_equal Time.local(2005,5,29,10),  Time.local(2005,6,5,10,0,0).weeks_ago(1)
+    assert_equal Time.local(2005,5,1,10), Time.local(2005,6,5,10,0,0).weeks_ago(5)
+    assert_equal Time.local(2005,4,24,10), Time.local(2005,6,5,10,0,0).weeks_ago(6)
+    assert_equal Time.local(2005,2,27,10),  Time.local(2005,6,5,10,0,0).weeks_ago(14)
+    assert_equal Time.local(2004,12,25,10),  Time.local(2005,1,1,10,0,0).weeks_ago(1)    
+  end
+
   def test_months_ago
     assert_equal Time.local(2005,5,5,10),  Time.local(2005,6,5,10,0,0).months_ago(1)
     assert_equal Time.local(2004,11,5,10), Time.local(2005,6,5,10,0,0).months_ago(7)
@@ -463,6 +471,16 @@ def test_utc_advance
     assert_equal Time.utc(2013,10,17,20,22,19), Time.utc(2005,2,28,15,15,10).advance(:years => 7, :months => 19, :weeks => 2, :days => 5, :hours => 5, :minutes => 7, :seconds => 9)
   end
 
+  def test_prev_week
+    with_env_tz 'US/Eastern' do
+      assert_equal Time.local(2005,2,21), Time.local(2005,3,1,15,15,10).prev_week
+      assert_equal Time.local(2005,2,22), Time.local(2005,3,1,15,15,10).prev_week(:tuesday)
+      assert_equal Time.local(2005,2,25), Time.local(2005,3,1,15,15,10).prev_week(:friday)
+      assert_equal Time.local(2006,10,30), Time.local(2006,11,6,0,0,0).prev_week
+      assert_equal Time.local(2006,11,15), Time.local(2006,11,23,0,0,0).prev_week(:wednesday)
+    end
+  end    
+
   def test_next_week
     with_env_tz 'US/Eastern' do
       assert_equal Time.local(2005,2,28), Time.local(2005,2,22,15,15,10).next_week

railties/guides/source/active_support_core_extensions.textile

@@ -2859,9 +2859,9 @@ d.end_of_week            # => Sun, 09 May 2010
 
 +beginning_of_week+ is aliased to +monday+ and +at_beginning_of_week+. +end_of_week+ is aliased to +sunday+ and +at_end_of_week+.
 
-h6. +next_week+
+h6. +prev_week+, +next_week+
 
-+next_week+ receives a symbol with a day name in English (in lowercase, default is +:monday+) and it returns the date corresponding to that day in the next week:
+The method +next_week+ receives a symbol with a day name in English (in lowercase, default is +:monday+) and it returns the date corresponding to that day:
 
 <ruby>
 d = Date.new(2010, 5, 9) # => Sun, 09 May 2010
@@ -2869,6 +2869,14 @@ d.next_week              # => Mon, 10 May 2010
 d.next_week(:saturday)   # => Sat, 15 May 2010
 </ruby>
 
+The method +prev_week+ is analogous:
+
+<ruby>
+d.prev_week              # => Mon, 26 Apr 2010
+d.prev_week(:saturday)   # => Sat, 01 May 2010
+d.prev_week(:friday)     # => Fri, 30 Apr 2010
+</ruby>
+
 h6. +beginning_of_month+, +end_of_month+
 
 The methods +beginning_of_month+ and +end_of_month+ return the dates for the beginning and end of the month:
@@ -2946,6 +2954,15 @@ Date.new(2010, 4, 30).months_ago(2)    # => Sun, 28 Feb 2010
 Date.new(2009, 12, 31).months_since(2) # => Sun, 28 Feb 2010
 </ruby>
 
+h6. +weeks_ago+
+
+The method +weeks_ago+ works analogously for weeks:
+
+<ruby>
+Date.new(2010, 5, 24).weeks_ago(1)    # => Mon, 17 May 2010
+Date.new(2010, 5, 24).weeks_ago(2)    # => Mon, 10 May 2010
+</ruby>
+
 h6. +advance+
 
 The most generic way to jump to other days is +advance+. This method receives a hash with keys +:years+, +:months+, +:weeks+, +:days+, and returns a date advanced as much as the present keys indicate:
@@ -3067,6 +3084,8 @@ yesterday
 tomorrow
 beginning_of_week (monday, at_beginning_of_week)
 end_on_week (at_end_of_week)
+weeks_ago
+prev_week
 next_week
 months_ago
 months_since
@@ -3239,6 +3258,8 @@ beginning_of_day (midnight, at_midnight, at_beginning_of_day)
 end_of_day
 beginning_of_week (monday, at_beginning_of_week)
 end_on_week (at_end_of_week)
+weeks_ago
+prev_week
 next_week
 months_ago
 months_since