Merge pull request #36 from Shopify/region_lookup_by_code_using_hash_2023-11-07

Improve performance by using hash table for by-code region lookup

Author: devanandersen

CHANGELOG.md

@@ -26,6 +26,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 
 - Add region name alternates [#32](https://github.com/Shopify/worldwide/pull/32)
 - Cache `Region#parent_name` [#33](https://github.com/Shopify/worldwide/pull/33)
+- Use hash tables to look up regions by code [#36](https://github.com/Shopify/worldwide/pull/36)
 
 ---
 

lib/worldwide/regions.rb

@@ -16,7 +16,7 @@ class << self
     end
 
     def initialize
-      @regions = RegionsLoader.new.load_regions
+      @regions, @regions_by_cldr_code, @regions_by_iso_code = RegionsLoader.new.load_regions
     end
 
     def all
@@ -29,17 +29,9 @@ def region(cldr: nil, code: nil, name: nil)
       end
 
       result = if cldr
-        search_code = cldr.to_s.upcase
-
-        @regions.find do |r|
-          r.send(:answers_to_cldr_code, search_code)
-        end
+        @regions_by_cldr_code[cldr.to_s.upcase]
       elsif code
-        search_code = code.to_s.upcase
-
-        @regions.find do |r|
-          r.send(:answers_to_iso_code, search_code) || r.alpha_three == search_code || r.numeric_three == search_code
-        end
+        @regions_by_iso_code[code.to_s.upcase]
       else # search by name
         search_name = name.upcase
 

lib/worldwide/regions_loader.rb

@@ -9,6 +9,9 @@ class RegionsLoader
     WORLD_CODE = "001" # UN code for the whole world
 
     def load_regions
+      @regions_by_cldr_code = {}
+      @regions_by_iso_code = {}
+
       # Load country/region definitions out of the db/data/regions/??.yml files
       @regions = Dir["#{Worldwide::Paths::REGIONS_ROOT}/*.yml"].map do |filename|
         load_territory(filename)
@@ -25,11 +28,39 @@ def load_regions
 
       construct_unknown
 
-      @regions.freeze
+      @regions.each do |region|
+        construct_lookup_info(region)
+      end
+
+      [@regions.freeze, @regions_by_cldr_code, @regions_by_iso_code]
     end
 
     private
 
+    def construct_lookup_info(region)
+      pc = region.send(:parent_country)
+
+      # Remember CLDR code(s) for later use during lookup
+
+      search_code = region.cldr_code.to_s.upcase
+      @regions_by_cldr_code[search_code] = region if Util.present?(search_code)
+
+      @regions_by_cldr_code["#{pc.cldr_code.upcase}#{search_code}"] = region if Util.present?(pc&.cldr_code)
+
+      # Remember ISO 3166 code(s) for later use during lookup
+
+      iso_code = region.iso_code
+      @regions_by_iso_code[iso_code] = region if Util.present?(iso_code)
+
+      @regions_by_iso_code["#{pc.iso_code}-#{iso_code}"] = region if Util.present?(pc)
+
+      alpha_three = region.alpha_three
+      @regions_by_iso_code[alpha_three] = region if Util.present?(alpha_three)
+
+      numeric_three = region.numeric_three
+      @regions_by_iso_code[numeric_three] = region if Util.present?(numeric_three)
+    end
+
     def apply_hierarchy(parent:, code:, children:)
       current_region = find_region(code: code)
       if current_region.nil?