FEATURE: Allow plugins to register a new locale

lib/js_locale_helper.rb

@@ -85,6 +85,7 @@ module JsLocaleHelper
   end
 
   def self.load_translations_merged(*locales)
+    locales = locales.compact
     @loaded_merges ||= {}
     @loaded_merges[locales.join('-')] ||= begin
       all_translations = {}
@@ -101,9 +102,10 @@ module JsLocaleHelper
   end
 
   def self.translations_for(locale_str)
-    current_locale = I18n.locale
-    locale_sym     = locale_str.to_sym
-    site_locale    = SiteSetting.default_locale.to_sym
+    current_locale  = I18n.locale
+    locale_sym      = locale_str.to_sym
+    site_locale     = SiteSetting.default_locale.to_sym
+    fallback_locale = LocaleSiteSetting.fallback_locale(locale_str)
 
     I18n.locale = locale_sym
 
@@ -113,9 +115,9 @@ module JsLocaleHelper
       elsif locale_sym == :en
         load_translations(locale_sym)
       elsif locale_sym == site_locale || site_locale == :en
-        load_translations_merged(locale_sym, :en)
+        load_translations_merged(locale_sym, fallback_locale, :en)
       else
-        load_translations_merged(locale_sym, site_locale, :en)
+        load_translations_merged(locale_sym, fallback_locale, site_locale, :en)
       end
 
     I18n.locale = current_locale
@@ -125,11 +127,13 @@ module JsLocaleHelper
 
   def self.output_locale(locale)
     locale_str = locale.to_s
+    fallback_locale_str = LocaleSiteSetting.fallback_locale(locale_str)&.to_s
     translations = Marshal.load(Marshal.dump(translations_for(locale_str)))
 
     message_formats = strip_out_message_formats!(translations[locale_str]['js'])
     message_formats.merge!(strip_out_message_formats!(translations[locale_str]['admin_js']))
-    result = generate_message_format(message_formats, locale_str)
+    mf_locale, mf_filename = find_message_format_locale([locale_str], true)
+    result = generate_message_format(message_formats, mf_locale, mf_filename)
 
     translations.keys.each do |l|
       translations[l].keys.each do |k|
@@ -140,7 +144,8 @@ module JsLocaleHelper
     # I18n
     result << "I18n.translations = #{translations.to_json};\n"
     result << "I18n.locale = '#{locale_str}';\n"
-    result << "I18n.pluralizationRules.#{locale_str} = MessageFormat.locale.#{locale_str};\n" if locale_str != "en"
+    result << "I18n.fallbackLocale = '#{fallback_locale_str}';\n" if fallback_locale_str && fallback_locale_str != "en"
+    result << "I18n.pluralizationRules.#{locale_str} = MessageFormat.locale.#{mf_locale};\n" if mf_locale != "en"
 
     # moment
     result << File.read("#{Rails.root}/lib/javascripts/moment.js")
@@ -150,6 +155,41 @@ module JsLocaleHelper
     result
   end
 
+  def self.find_moment_locale(locale_chain)
+    path = "#{Rails.root}/lib/javascripts/moment_locale"
+
+    # moment.js uses a different naming scheme for locale files
+    locale_chain = locale_chain.map { |l| l.tr('_', '-').downcase }
+
+    find_locale(locale_chain, path, :moment_js, false)
+  end
+
+  def self.find_message_format_locale(locale_chain, fallback_to_english)
+    path = "#{Rails.root}/lib/javascripts/locale"
+    find_locale(locale_chain, path, :message_format, fallback_to_english)
+  end
+
+  def self.find_locale(locale_chain, path, type, fallback_to_english)
+    locale_chain.each do |locale|
+      plugin_locale = DiscoursePluginRegistry.locales[locale]
+      return plugin_locale[type] if plugin_locale&.has_key?(type)
+
+      filename = File.join(path, "#{locale}.js")
+      return [locale, filename] if File.exist?(filename)
+    end
+
+    # try again, but this time only with the language itself
+    locale_chain = locale_chain.map { |l| l.split(/[-_]/)[0] }
+      .uniq.reject { |l| locale_chain.include?(l) }
+    unless locale_chain.empty?
+      locale_data = find_locale(locale_chain, path, type, false)
+      return locale_data if locale_data
+    end
+
+    # English should alyways work
+    ["en", File.join(path, "en.js")] if fallback_to_english
+  end
+
   def self.moment_formats
     result = ""
     result << moment_format_function('short_date_no_year')
@@ -163,23 +203,13 @@ module JsLocaleHelper
     "moment.fn.#{name.camelize(:lower)} = function(){ return this.format('#{format}'); };\n"
   end
 
-  def self.moment_locale(locale_str)
-    # moment.js uses a different naming scheme for locale files
-    locale_str = locale_str.tr('_', '-').downcase
-    filename = "#{Rails.root}/lib/javascripts/moment_locale/#{locale_str}.js"
-
-    # try the language without the territory
-    locale_str = locale_str.split("-")[0]
-    filename = "#{Rails.root}/lib/javascripts/moment_locale/#{locale_str}.js" unless File.exists?(filename)
-
-    File.exists?(filename) ? File.read(filename) << "\n" : ""
+  def self.moment_locale(locale)
+    _, filename = find_moment_locale([locale])
+    filename && File.exist?(filename) ? File.read(filename) << "\n" : ""
   end
 
-  def self.generate_message_format(message_formats, locale_str)
-    formats = message_formats.map { |k, v| k.inspect << " : " << compile_message_format(locale_str, v) }.join(", ")
-
-    filename = "#{Rails.root}/lib/javascripts/locale/#{locale_str}.js"
-    filename = "#{Rails.root}/lib/javascripts/locale/en.js" unless File.exists?(filename)
+  def self.generate_message_format(message_formats, locale, filename)
+    formats = message_formats.map { |k, v| k.inspect << " : " << compile_message_format(filename, locale, v) }.join(", ")
 
     result = "MessageFormat = {locale: {}};\n"
     result << "I18n._compiledMFs = {#{formats}};\n"
@@ -203,10 +233,9 @@ module JsLocaleHelper
     end
   end
 
-  def self.compile_message_format(locale, format)
+  def self.compile_message_format(path, locale, format)
     with_context do |ctx|
-      path = "#{Rails.root}/lib/javascripts/locale/#{locale}.js"
-      ctx.load(path) if File.exists?(path)
+      ctx.load(path) if File.exist?(path)
       ctx.eval("mf = new MessageFormat('#{locale}');")
       ctx.eval("mf.precompile(mf.parse(#{format.inspect}))")
     end