Pluralize common variant unit names

This adds the most popular unit names as singular and plural to our
locale for translation. The added Javascript performs a reverse lookup
to find the right singular/plural form of a unit name in that language.

app/assets/javascripts/admin/products/services/option_value_namer.js.coffee

@@ -21,9 +21,7 @@ angular.module("admin.products").factory "OptionValueNamer", (VariantUnitManager
 
         else
           value = @variant.unit_value
-          unit_name = @variant.product.variant_unit_name
-          # TODO needs to add pluralize to line below
-          # unit_name = unit_name if value > 1
+          unit_name = @pluralize(@variant.product.variant_unit_name, value)
 
         value = parseInt(value, 10) if value == parseInt(value, 10)
 
@@ -32,6 +30,21 @@ angular.module("admin.products").factory "OptionValueNamer", (VariantUnitManager
 
       [value, unit_name]
 
+    pluralize: (unit_name, count) ->
+      return unit_name if count == undefined
+      unit_key = @unit_key(unit_name)
+      return unit_name unless unit_key
+      I18n.t(["unit_names", unit_key], {count: count, defaultValue: unit_name})
+
+    unit_key: (unit_name) ->
+      unless I18n.unit_keys
+        I18n.unit_keys = {}
+        for key, translations of I18n.t("unit_names")
+          for quantifier, translation of translations
+            I18n.unit_keys[translation.toLowerCase()] = key
+
+      I18n.unit_keys[unit_name.toLowerCase()]
+
     option_value_value_unit_scaled: ->
       [unit_scale, unit_name] = @scale_for_unit_value()
 

config/locales/en.yml

@@ -2721,6 +2721,101 @@ See the %{link} to find out more about %{sitename}'s features and to start using
       have_an_account: "Already have an account?"
       action_login: "Log in now."
 
+  # Most popular names used in variant_unit_name.
+  # We use these entries to pluralize unit names in every language.
+  #
+  # Extracted with the following query:
+  # Spree::Product.group(:variant_unit_name).order("count_all DESC").count.each { |name, count|
+  #   puts "    # Used #{count} times."
+  #   puts "    #{name&.parameterize('_')}:"
+  #   puts "      one: \"#{name}\""
+  #   puts "      other: \"#{name}s\"";
+  # }
+  unit_names:
+    # Used 379 times.
+    # Used 138 times.
+    each:
+      one: "each"
+      other: "each"
+    # Used 332 times.
+    # Used 145 times.
+    # Used 93 times.
+    bunch:
+      one: "bunch"
+      other: "bunches"
+    # Used 118 times.
+    # Used 63 times.
+    pack:
+      one: "pack"
+      other: "packs"
+    # Used 90 times.
+    # Used 72 times.
+    box:
+      one: "box"
+      other: "boxes"
+    # Used 81 times.
+    # Used 49 times.
+    bottle:
+      one: "bottle"
+      other: "bottles"
+    # Used 71 times.
+    # Used 56 times.
+    jar:
+      one: "jar"
+      other: "jars"
+    # Used 65 times.
+    head:
+      one: "head"
+      other: "heads"
+    # Used 56 times.
+    # Used 41 times.
+    bag:
+      one: "bag"
+      other: "bags"
+    # Used 53 times.
+    # Used 30 times.
+    loaf:
+      one: "loaf"
+      other: "loaves"
+    # Used 43 times.
+    single:
+      one: "single"
+      other: "singles"
+    # Used 41 times.
+    tub:
+      one: "tub"
+      other: "tubs"
+    # Used 36 times.
+    punnet:
+      one: "punnet"
+      other: "punnets"
+    # Used 32 times.
+    packet:
+      one: "packet"
+      other: "packets"
+    # Used 30 times.
+    # Used 22 times.
+    item:
+      one: "item"
+      other: "items"
+    # Used 29 times.
+    # Used 24 times.
+    dozen:
+      one: "dozen"
+      other: "dozens"
+    # Used 26 times.
+    unit:
+      one: "unit"
+      other: "units"
+    # Used 24 times.
+    serve:
+      one: "serve"
+      other: "serves"
+    # Used 20 times.
+    tray:
+      one: "tray"
+      other: "trays"
+
   producers:
     signup:
       start_free_profile: "Start with a free profile, and expand when you're ready!"

spec/javascripts/unit/admin/products/services/option_value_namer_spec.js.coffee

@@ -0,0 +1,26 @@
+describe "OptionValueNamer", ->
+  subject = null
+
+  beforeEach ->
+    module('admin.products')
+    inject (_OptionValueNamer_) ->
+      subject = new _OptionValueNamer_
+
+  describe "pluralize a variant unit name", ->
+    it "returns the same word if no plural is known", ->
+      expect(subject.pluralize("foo", 2)).toEqual "foo"
+
+    it "returns the same word if we omit the quantity", ->
+      expect(subject.pluralize("loaf")).toEqual "loaf"
+
+    it "finds the plural of a word", ->
+      expect(subject.pluralize("loaf", 2)).toEqual "loaves"
+
+    it "finds the singular of a word", ->
+      expect(subject.pluralize("loaves", 1)).toEqual "loaf"
+
+    it "finds the zero form of a word", ->
+      expect(subject.pluralize("loaf", 0)).toEqual "loaves"
+
+    it "ignores upper case", ->
+      expect(subject.pluralize("Loaf", 2)).toEqual "loaves"