Playing with date formatting in liquid templates - Useful in Harmonia task titles

liquid-templates-and-date-formats.rb

require 'bundler/inline'

gemfile do
  source 'https://rubygems.org'
  gem 'liquid'
  gem 'bigdecimal'
end

require 'date'
require 'liquid'

GFR_INCORPORATION_DATE = Date.parse('2009-01-12').strftime('%s')
SECONDS_IN_A_WEEK = 7 * 24 * 60 * 60
SECONDS_IN_A_MONTH = 28 * 24 * 60 * 60

def render_template(template, input)
  liquid_template = Liquid::Template.parse(template)
  liquid_template.render(input)
end

def display_template(title, template)
  input = {'due' => Date.today}

  puts <<-EndOutput
## #{title}

```
#{template}
```

* Input: #{input}
* Output: #{render_template(template, input)}

---

EndOutput
end

template = <<-EndTemplate
{{ due |
   date: '%s' |
   minus: #{GFR_INCORPORATION_DATE} |
   divided_by: #{SECONDS_IN_A_WEEK}
}}
EndTemplate
display_template('Current GFR week', template)

template = <<-EndTemplate
{{ due |
   date: '%s' |
   minus: #{GFR_INCORPORATION_DATE} |
   minus: #{SECONDS_IN_A_WEEK} |
   divided_by: #{SECONDS_IN_A_WEEK}
}}
EndTemplate
display_template('Previous GFR week', template)

template = <<-EndTemplate
{{ due |
   date: "%b %Y"
}}
EndTemplate
display_template('Current month', template)

template = <<-EndTemplate
{{ due |
   date: "%s" |
   minus: #{SECONDS_IN_A_MONTH} |
   date: "%b %Y"
}}
EndTemplate
display_template('Last month', template)

template = <<-EndTemplate
{{ due |
   date: "%F"
}}
EndTemplate
display_template('Current date', template)

template = <<-EndTemplate
{{ due |
   date: "%Y"
}}
EndTemplate
display_template('Current year', template)

template = <<-EndTemplate
{{ due |
   date: "%Y" |
   minus: 1
}}
EndTemplate
display_template('Last year', template)

output.md

Current GFR week

{{ due |
   date: '%s' |
   minus: 1231718400 |
   divided_by: 604800
}}

• Input: {"due"=>#<Date: 2017-05-02 ((2457876j,0s,0n),+0s,2299161j)>}
• Output: 433

---

Previous GFR week

{{ due |
   date: '%s' |
   minus: 1231718400 |
   minus: 604800 |
   divided_by: 604800
}}

• Input: {"due"=>#<Date: 2017-05-02 ((2457876j,0s,0n),+0s,2299161j)>}
• Output: 432

---

Current month

{{ due |
   date: "%b %Y"
}}

• Input: {"due"=>#<Date: 2017-05-02 ((2457876j,0s,0n),+0s,2299161j)>}
• Output: May 2017

---

Last month

{{ due |
   date: "%s" |
   minus: 2419200 |
   date: "%b %Y"
}}

• Input: {"due"=>#<Date: 2017-05-02 ((2457876j,0s,0n),+0s,2299161j)>}
• Output: Apr 2017

---

Current date

{{ due |
   date: "%F"
}}

• Input: {"due"=>#<Date: 2017-05-02 ((2457876j,0s,0n),+0s,2299161j)>}
• Output: 2017-05-02