til/rails/look-up-time-zone-info-for-identifier.md

Look Up Time Zone Info For Identifier

The ActiveSupport::TimeZone class overrides the #[] method to be a lookup mechanism for IANA Time Zone Identifier strings. These are strings like America/Chicago (or anything else listed under TZInfo::Timezone.all).

Let's get an instance for America/Chicago.

> chi = ActiveSupport::TimeZone['America/Chicago']
=> #<ActiveSupport::TimeZone:0x00000001099d8140
 @name="America/Chicago",
 @tzinfo=#<TZInfo::DataTimezone: America/Chicago>,
 @utc_offset=nil>

Notice it has a tzinfo instance variable that we can access. That object contains all kinds of useful things.

> chi.tzinfo.name
=> "America/Chicago"
> chi.tzinfo.friendly_identifier
=> "America - Chicago"
> chi.tzinfo.abbr
=> "CDT"
> chi.tzinfo.utc_offset
=> -18000
> chi.tzinfo.dst?
=> true

All of these and more. Run ls chi.tzinfo in a pry session to see what else.