Class: UnitHelper

Inherits:
Object
  • Object
show all
Defined in:
lib/unit_helper.rb

Overview

Simple class to provide a wrapper/common pattern around Ruby-Units

Class Method Summary collapse

Class Method Details

.abbreviation(unit) ⇒ String

Unit is a RubyUnits::UnitDefinition

Returns:

  • (String) —

    the unit abbreviation



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# File 'lib/unit_helper.rb', line 22

def abbreviation(unit)
  unit.aliases.first
end

.all_units(add_kind: false) ⇒ Array

Returns the cached unit list.

Returns:

  • (Array) —

    the cached unit list



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# File 'lib/unit_helper.rb', line 45

def all_units(add_kind: false)
  Rails.cache.fetch([:units, :all, I18n.locale, :v9], expires_in: 1.week) do
    units_by_kind(:all, add_kind: add_kind)
  end
end

.display_name(unit) ⇒ String

Unit is a RubyUnits::UnitDefinition

Returns:

  • (String) —

    the localized display name



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# File 'lib/unit_helper.rb', line 12

def display_name(unit)
  # the longest aliases seems the nicest compared to the display_name
  name_en = unit.aliases.max_by(&:length).titleize
  return name_en if I18n.locale.to_s.first(2) == 'en'

  TranslationKey.translate(name_en, I18n.locale, namespace: 'Units')
end

.kind_of_units ⇒ Array<Symbol>

Returns the available unit kinds.

Returns:

  • (Array<Symbol>) —

    the available unit kinds



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# File 'lib/unit_helper.rb', line 6

def kind_of_units
  RubyUnits::Unit.definitions.values.map(&:kind).uniq
end

.length_units ⇒ Array

Returns length units.

Returns:

  • (Array) —

    length units



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# File 'lib/unit_helper.rb', line 52

def length_units
  units_by_kind(:length)
end

.mass_units ⇒ Array

Returns mass units.

Returns:

  • (Array) —

    mass units



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# File 'lib/unit_helper.rb', line 57

def mass_units
  units_by_kind(:mass)
end

.unit_symbol(unit) ⇒ String?

Returns the display symbol for the unit.

Returns:

  • (String, nil) —

    the display symbol for the unit



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# File 'lib/unit_helper.rb', line 62

def unit_symbol(unit)
  case unit&.downcase
  when 'degf'
    " °F" # could be ℉ but seem too compressed
  when 'degc'
    " °C" # or ℃
  when 'ohm'
    " Ω"
  when "hertz"
    " ㎐"
  # when "kg"
  #   "㎏"
  when "ft"
    "′"
  when "in"
    "″"
  when "sqft"
    " ft²"
  when "sqin"
    " in²"
  when "m2"
    " m²"
  else
    " #{unit}"
  end
end

.units_by_kind(kind, add_kind: false) ⇒ Array<Array(String, String)>

Returns [display name, abbreviation] pairs.

Returns:

  • (Array<Array(String, String)>) —

    [display name, abbreviation] pairs



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# File 'lib/unit_helper.rb', line 27

def units_by_kind(kind, add_kind: false)
  udv = RubyUnits::Unit.definitions.values
  udv.select! { |d| d.kind.to_s == kind.to_s } unless kind == :all || kind.nil?
  # Reject prefixes stuff
  udv.reject! { |d| d.kind == :prefix }
  udv.map do |ud|
    n = display_name(ud)
    v = abbreviation(ud)
    unless n.casecmp(v).zero?
      # We append the abbreviation in the name
      n = "#{n} (#{v})"
    end
    n = "#{n} [#{ud.kind}]" if add_kind
    [n, v]
  end
end