Add custom DateTime format in Rails

Global time format for entire Rails App

# config/initializers/time_formats.rb
Time::DATE_FORMATS[:us] = "%m/%d/%Y %I:%M %p"

# spec/config/initializers/time_formats_spec.rb
RSpec.describe "Custom Time Formats" do
  describe "us time format" do
    it do
      time = Time.parse "2013-12-11 10:09:08"
      expect(time.to_fs(:us)).to eq("12/11/2013 10:09 AM")
    end
  end
end

Locales time format (translations)

usage by l helper is not using custom defined formats in Time::DATE_FORMATS as format is different from country to country (e.g US vs GB time)

https://www.rubydoc.info/gems/i18n/I18n/Backend/Base:localize

# config/locales/en.yml
en:
  time:
    formats:
      admin: "%m/%d/%Y"

# show.html.erb
<%= l @company.created_at, format: :admin %>