Refactor Date, Time, DateTime timezone methods

Similar implementations of #in_time_zone exists for Date, Time and DateTime so
method is extracted into its own module. Also some logic is extracted into
private method.

1 files changed, 41 insertions, 0 deletions

diff --git a/activesupport/lib/active_support/core_ext/date_and_time/zones.rb b/activesupport/lib/active_support/core_ext/date_and_time/zones.rb
new file mode 100644
index 0000000000..96c6df9407
--- /dev/null
+++ b/activesupport/lib/active_support/core_ext/date_and_time/zones.rb
@@ -0,0 +1,41 @@
+module DateAndTime
+  module Zones
+    # Returns the simultaneous time in <tt>Time.zone</tt> if a zone is given or
+    # if Time.zone_default is set. Otherwise, it returns the current time.
+    #
+    #   Time.zone = 'Hawaii'        # => 'Hawaii'
+    #   DateTime.utc(2000).in_time_zone # => Fri, 31 Dec 1999 14:00:00 HST -10:00
+    #   Date.new(2000).in_time_zone  # => Sat, 01 Jan 2000 00:00:00 HST -10:00
+    #
+    # This method is similar to Time#localtime, except that it uses <tt>Time.zone</tt> as the local zone
+    # instead of the operating system's time zone.
+    #
+    # You can also pass in a TimeZone instance or string that identifies a TimeZone as an argument,
+    # and the conversion will be based on that zone instead of <tt>Time.zone</tt>.
+    #
+    #   Time.utc(2000).in_time_zone('Alaska') # => Fri, 31 Dec 1999 15:00:00 AKST -09:00
+    #   DateTime.utc(2000).in_time_zone('Alaska') # => Fri, 31 Dec 1999 15:00:00 AKST -09:00
+    #   Date.new(2000).in_time_zone('Alaska')  # => Sat, 01 Jan 2000 00:00:00 AKST -09:00
+    def in_time_zone(zone = ::Time.zone)
+      time_zone = ::Time.find_zone! zone
+      time = acts_like?(:time) ? self : nil
+
+      if time_zone
+        time_with_zone(time, time_zone)
+      else
+        time || self.to_time
+      end
+    end
+
+    private
+
+    def time_with_zone(time, zone)
+      if time
+        ActiveSupport::TimeWithZone.new(time.utc? ? time : time.getutc, zone)
+      else
+        ActiveSupport::TimeWithZone.new(nil, zone, to_time(:utc))
+      end
+    end
+  end
+end
+