EraJa

Convert to Japanese era.

Add this line to your application's Gemfile:

gem 'era_ja'

And then execute:

$ bundle

Or install it yourself as:

$ gem install era_ja

See .travis.yml

NOTE :: era_ja does not support ruby 1.9.3 since 0.4.0

strftime format string can be used as an argument.

Extra format strings provided by EraJa#to_era are:

• %o: era(alphabet)
• %O: era(kanzi)
• %1O: era(single kanzi)
• %E: era year
• %-E: era year(single digit format from 1 to 9)
• %K: era year(kanzi numeral) After the second year, make it a numeral
• %J: kanzi numeral

require 'era_ja'
Time.mktime(2012,4,29).to_era   # => "H24.04.29"
Time.mktime(2012,4,29).to_era("%O%E年%-m月%d日") # => "平成24年4月29日"
Time.mktime(2012,4,29).to_era("%O%JE年%Jm月%Jd日") # => "平成二十四年四月二十九日"

require 'era_ja'
Date.new(2012,4,29).to_era     # => "H24.04.29"
Date.new(2012,4,29).to_era("%O%E年%-m月%d日") # => "平成24年4月29日"
Date.new(2012,4,29).to_era("%O%JE年%Jm月%Jd日") # => "平成二十四年四月二十九日"

Time.mktime(2012,4,29).to_era("%JY年%Jm月%Jd日") # => "二千十二年四月二十九日"
Date.new(2012,4,29).to_era("%JY年%Jm月%Jd日")    # => "二千十二年四月二十九日"

The first year to be 元 and the second and subsequent years to be numbers, you can use %K.

Time.mktime(2019,5,1).to_era("%O%KE年%m月%d日") # => "令和元年05月01日"
Time.mktime(2020,5,1).to_era("%O%KE年%m月%d日") # => "令和02年05月01日"
Date.new(2019,5,1).to_era("%O%KE年%m月%d日") # => "令和元年05月01日"
Date.new(2020,5,1).to_era("%O%KE年%m月%d日") # => "令和02年05月01日"

To convert to single kanji era strings, you can use %1O.

require 'era_ja'
Time.mktime(2012,4,29).to_era("%1O%E年%m月%d日") # => "平24年4月29日"

To convert to custom era strings, you can set era_names .

require 'era_ja'
Time.mktime(2012,4,29).to_era(era_names: { heisei: ['h', '平'] })                       # => "h24.04.29"
Time.mktime(2012,4,29).to_era("%O%E年%-m月%d日", era_names: { heisei: ['h', '平'] })     # => "平24年4月29日"
Time.mktime(2012,4,29).to_era("%O%JE年%Jm月%Jd日", era_names: { heisei: ['h', '平'] })   # => "平二十四年四月二十九日"
# same as Date

You can use era_convertible? to check if a given date is convertible or not.

require 'era_ja'
Time.mktime(1868,9,7).era_convertible? #=> false
Time.mktime(1868,9,8).era_convertible? #=> true

See Note section for more details.

Report issues and feature requests to github Issues. https://github.com/tomiacannondale/era_ja/issues

1. Fork it
2. Create your feature branch (git checkout -b my-new-feature)
3. Commit your changes (git commit -am 'Added some feature')
4. Push to the branch (git push origin my-new-feature)
5. Create a new Pull Request

The following issues exist regarding era:

• The Meiji era starts at September 8, 1866, but that date is in the old Japanese lunar calendar.
• The start dates of the Taisho and Showa eras are the same as the end dates of the Meiji and Taisho eras respectively.
  • 昭和ト改元
  • 大正十五年十二月ニ十五日以後ヲ改メテ昭和元年ト爲ス
  • 明治45年（1912）7月｜大正と改元：日本のあゆみ

tomi tomiacannondale@gmail.com

MIT License. For more information, please see LICENSE.