memoize keys

Gemfile.lock

@@ -1,7 +1,7 @@
 PATH
   remote: .
   specs:
-    case_transform (0.1)
+    case_transform (0.2)
       activesupport
 
 GEM

lib/case_transform.rb

@@ -5,7 +5,22 @@
 require 'case_transform/version'
 
 module CaseTransform
-  module_function
+  class << self
+    def camel_cache
+      @camel_cache ||= {}
+    end
+
+    def camel_lower_cache
+      @camel_lower_cache ||= {}
+    end
+
+    def dash_cache
+      @dash_cache ||= {}
+    end
+
+    def underscore_cache
+      @underscore_cache ||= {}
+    end
 
     # Transforms values to UpperCamelCase or PascalCase.
     #
@@ -16,7 +31,7 @@ def camel(value)
       when Array then value.map { |item| camel(item) }
       when Hash then value.deep_transform_keys! { |key| camel(key) }
       when Symbol then camel(value.to_s).to_sym
-      when String then value.underscore.camelize
+      when String then camel_cache[value] ||= value.underscore.camelize
       else value
       end
     end
@@ -30,7 +45,7 @@ def camel_lower(value)
       when Array then value.map { |item| camel_lower(item) }
       when Hash then value.deep_transform_keys! { |key| camel_lower(key) }
       when Symbol then camel_lower(value.to_s).to_sym
-      when String then value.underscore.camelize(:lower)
+      when String then camel_lower_cache[value] ||= value.underscore.camelize(:lower)
       else value
       end
     end
@@ -45,7 +60,7 @@ def dash(value)
       when Array then value.map { |item| dash(item) }
       when Hash then value.deep_transform_keys! { |key| dash(key) }
       when Symbol then dash(value.to_s).to_sym
-      when String then value.underscore.dasherize
+      when String then dash_cache[value] ||= value.underscore.dasherize
       else value
       end
     end
@@ -60,7 +75,7 @@ def underscore(value)
       when Array then value.map { |item| underscore(item) }
       when Hash then value.deep_transform_keys! { |key| underscore(key) }
       when Symbol then underscore(value.to_s).to_sym
-      when String then value.underscore
+      when String then underscore_cache[value] ||= value.underscore
       else value
       end
     end
@@ -69,4 +84,5 @@ def underscore(value)
     def unaltered(value)
       value
     end
+  end
 end

lib/case_transform/version.rb

@@ -1,4 +1,4 @@
 # frozen_string_literal: true
 module CaseTransform
-  VERSION = '0.1'.freeze
+  VERSION = '0.2'.freeze
 end