• Prekin means PREMIUM FRIDAY
  • kin means FRIDAY (kin-yo-bi) in Japanese
  • So PREmium KIN-yo-bi is Prekin

• A webpage by Ministry of Economy, Trade and Industry in Japan
  • http://www.meti.go.jp/policy/mono_info_service/service/premium-friday/
• A webpage by Premium Friday Committee
  • https://web.archive.org/web/20230411145908if_/https://premium-friday.com/

Add this line to your application's Gemfile:

gem 'prekin'

And then execute:

$ bundle

Or install it yourself as:

$ gem install prekin

• require 'prekin'

• Time.local(2020, 10, 30, 0, 0, 0).prekin? #=> true

• Date.new(2020, 10, 30).prekin? #=> true

• DateTime.new(2020, 10, 30, 0, 0, 0, '+09:00').prekin? #=> true

• '2020/10/30 00:00:00 +09:00'.prekin? #=> true

• Prekin.next #=> "2020-10-30"
• Prekin.next('2023-12-28') #=> "2023-12-29"
• Prekin.next('2023-12-29') #=> "2023-12-29"
• Prekin.next('2023-12-30') #=> "2024-01-26"

• This gem overwrites Time, Date, DateTime and String class.
  • So if you use Time, Date, DateTime and String class in your code, you should be careful.

The gem is available as open source under the terms of the MIT License.