Add Get Formatted UTC Offset Value as a Rails TIL

README.md

@@ -10,7 +10,7 @@ pairing with smart people at Hashrocket.
 
 For a steady stream of TILs, [sign up for my newsletter](https://crafty-builder-6996.ck.page/e169c61186).
 
-_1409 TILs and counting..._
+_1410 TILs and counting..._
 
 ---
 
@@ -879,6 +879,7 @@ _1409 TILs and counting..._
 - [Get ActiveRecord Attribute Directly From Database](rails/get-active-record-attribute-directly-from-database.md)
 - [Get An Array Of Values From The Database](rails/get-an-array-of-values-from-the-database.md)
 - [Get An Empty ActiveRecord Relation](rails/get-an-empty-activerecord-relation.md)
+- [Get Formatted UTC Offset Value](rails/get-formatted-utc-offset-value.md)
 - [Get Help With A Rails App Update](rails/get-help-with-a-rails-app-update.md)
 - [Get The Column Names For A Model](rails/get-the-column-names-for-a-model.md)
 - [Get The Current Time](rails/get-the-current-time.md)

rails/get-formatted-utc-offset-value.md

@@ -0,0 +1,37 @@
+# Get Formatted UTC Offset Value
+
+The UTC offset (during DST) for Chicago is `-05:00`. And for Newfoundland it is
+`-02:30`.
+
+Rails has an [`ActiveSupport::TimeZone`
+module](https://api.rubyonrails.org/v7.1.3.2/classes/ActiveSupport/TimeZone.html#method-c-seconds_to_utc_offset)
+that can turn the UTC offset in seconds into this formatted value.
+
+```ruby
+> chicago = TZInfo::Timezone.get('America/Chicago')
+=> #<TZInfo::DataTimezone: America/Chicago>
+> ActiveSupport::TimeZone.seconds_to_utc_offset(chicago.utc_offset)
+=> "-05:00"
+
+> newfoundland = TZInfo::Timezone.get('America/St_Johns')
+=> #<TZInfo::DataTimezone: America/St_Johns>
+> ActiveSupport::TimeZone.seconds_to_utc_offset(newfoundland.utc_offset)
+=> "-02:30"
+```
+
+The underlying `tzinfo` gem is DST-aware and its database even knows which time
+zone identifiers don't observe DST, so you can run this anytime of the year and
+expect reliable results.
+
+Here is another way at this:
+
+```ruby
+> chicago = TZInfo::Timezone.get('America/Chicago')
+=> #<TZInfo::DataTimezone: America/Chicago>
+> ActiveSupport::TimeZone[chicago.name]
+=> #<ActiveSupport::TimeZone:0x00000001099d8140 @name="America/Chicago", @tzinfo=#<TZInfo::DataTimezone: America/Chicago>, @utc_offset=nil>
+> ActiveSupport::TimeZone[chicago.name].formatted_offset
+=> "-06:00"
+> ActiveSupport::TimeZone[chicago.name].formatted_offset(false)
+=> "-0600"
+```