Shouhizei

This gem support to calculate Japan consumption tax

Installation

Add this line to your application's Gemfile:

gem 'shouhizei'

And then execute:

$ bundle

Or install it yourself as:

$ gem install shouhizei

Usage

You can get Japanese consumption tax rate like below.

Shouhizei.rate_on(Time.zone.local(1989, 3, 31))
 => (0/1)

Shouhizei.rate_on(Time.zone.local(1989, 4, 1))
 => (3/100)

Shouhizei.rate_on(Time.zone.local(1997, 4, 1))
 => (1/20)

Shouhizei.rate_on(Time.zone.local(2014, 4, 1))
 => (2/25)

Shouhizei.rate_on(Time.zone.local(2019, 10, 1))
 => (1/10)

Shouhizei.rate_on(Time.zone.local(2019, 10, 1), reduced: true) # Return reduced tax rate
 => (2/25)

Shouhizei.rate_on # Returns the current consumption tax
 => (2/25)

This considers local timezone and changes to 'Asia/Tokyo' by using ActiveSupport::TimeWithZone#in_time_zone .

> Time.zone = 'Asia/Tokyo'
=> "Asia/Tokyo"
> Shouhizei.rate_on(Time.zone.local(1989, 3, 31, 10, 0, 0))
=> (0/1)
> Time.zone = 'Hawaii'
=> "Hawaii"
> Shouhizei.rate_on(Time.zone.local(1989, 3, 31, 10, 0, 0)) # 1989-04-01 05:00:00 in Japan
=> (3/100)

Calculation tax included price. Return value class is Integer.

Shouhizei.including(price: 100, time: Time.zone.local(2014, 4, 1))
 => 108 # return value class is Integer

Shouhizei.including(price: 100, time: Time.zone.local(2019, 10, 1), reduced: true)
 => 108 # return value with reduced tax in Integer

Configuration how to deal fraction round up or round down. Default is round down.

Shouhizei.config[:rounding] = Shouhizei::RoundUp
Shouhizei.including(price: 10)
 => 11

Shouhizei.config[:rounding] = Shouhizei::RoundDown
Shouhizei.including(price: 10)
 => 10

You can use rounding option when use including method.

Shouhizei.config[:rounding] = Shouhizei::RoundUp
Shouhizei.including(price: 10, rounding: Shouhizei::RoundDown)
 => 10

Shouhizei.config[:rounding] = Shouhizei::RoundDown
Shouhizei.including(price: 10, rounding: Shouhizei::RoundUp)
 => 10

Development

After checking out the repo, run bin/setup to install dependencies. Then, run rake test to run the tests. You can also run bin/console for an interactive prompt that will allow you to experiment.

To install this gem onto your local machine, run bundle exec rake install. To release a new version, update the version number in version.rb, and then run bundle exec rake release, which will create a git tag for the version, push git commits and tags, and push the .gem file to rubygems.org.

Contributing

Bug reports and pull requests are welcome on GitHub at https://github.com/colorbox/shouhizei. This project is intended to be a safe, welcoming space for collaboration, and contributors are expected to adhere to the Contributor Covenant code of conduct.

License

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

Code of Conduct

Everyone interacting in the Shouhizei project’s codebases, issue trackers, chat rooms and mailing lists is expected to follow the code of conduct.