Do some micro optimizations on strings

Author: n-rodriguez

lib/ajax-datatables-rails/datatable/column.rb

@@ -4,13 +4,18 @@ module AjaxDatatablesRails
   module Datatable
     class Column
 
+      TYPE_CAST_DEFAULT = 'VARCHAR'
+      TYPE_CAST_MYSQL   = 'CHAR'
+      TYPE_CAST_SQLITE  = 'TEXT'
+      TYPE_CAST_ORACLE  = 'VARCHAR2(4000)'
+
       DB_ADAPTER_TYPE_CAST = {
-        mysql:          'CHAR',
-        mysql2:         'CHAR',
-        sqlite:         'TEXT',
-        sqlite3:        'TEXT',
-        oracle:         'VARCHAR2(4000)',
-        oracleenhanced: 'VARCHAR2(4000)'
+        mysql:          TYPE_CAST_MYSQL,
+        mysql2:         TYPE_CAST_MYSQL,
+        sqlite:         TYPE_CAST_SQLITE,
+        sqlite3:        TYPE_CAST_SQLITE,
+        oracle:         TYPE_CAST_ORACLE,
+        oracleenhanced: TYPE_CAST_ORACLE
       }.freeze
 
       attr_reader :datatable, :index, :options
@@ -65,7 +70,7 @@ def formatted_value
       private
 
       def type_cast
-        @type_cast ||= (DB_ADAPTER_TYPE_CAST[AjaxDatatablesRails.config.db_adapter] || 'VARCHAR')
+        @type_cast ||= DB_ADAPTER_TYPE_CAST.fetch(AjaxDatatablesRails.config.db_adapter, TYPE_CAST_DEFAULT)
       end
 
       def casted_column

lib/ajax-datatables-rails/datatable/column/search.rb

@@ -6,7 +6,9 @@ class Column
       module Search
 
         SMALLEST_PQ_INTEGER = -2147483648
-        LARGEST_PQ_INTEGER = 2147483647
+        LARGEST_PQ_INTEGER  = 2147483647
+        NOT_NULL_VALUE      = '!NULL'
+        EMPTY_VALUE         = ''
 
         def searchable?
           @view_column.fetch(:searchable, true)
@@ -74,7 +76,7 @@ def non_regex_search
         end
 
         def null_value_search
-          if formatted_value == '!NULL'
+          if formatted_value == NOT_NULL_VALUE
             table[field].not_eq(nil)
           else
             table[field].eq(nil)
@@ -90,7 +92,7 @@ def raw_search(cond)
         end
 
         def empty_search
-          casted_column.matches('')
+          casted_column.matches(EMPTY_VALUE)
         end
 
         def is_searchable_integer?

lib/ajax-datatables-rails/datatable/datatable.rb

@@ -3,8 +3,6 @@
 module AjaxDatatablesRails
   module Datatable
 
-    TRUE_VALUE = 'true'
-
     class Datatable
       attr_reader :datatable, :options
 

lib/ajax-datatables-rails/datatable/simple_order.rb

@@ -4,7 +4,9 @@ module AjaxDatatablesRails
   module Datatable
     class SimpleOrder
 
-      DIRECTIONS = %w[DESC ASC].freeze
+      DIRECTION_ASC  = 'ASC'
+      DIRECTION_DESC = 'DESC'
+      DIRECTIONS     = [DIRECTION_ASC, DIRECTION_DESC].freeze
 
       def initialize(datatable, options = {})
         @datatable = datatable
@@ -24,7 +26,7 @@ def column
       end
 
       def direction
-        DIRECTIONS.find { |dir| dir == column_direction } || 'ASC'
+        DIRECTIONS.find { |dir| dir == column_direction } || DIRECTION_ASC
       end
 
       private

lib/ajax-datatables-rails/datatable/simple_search.rb

@@ -4,6 +4,8 @@ module AjaxDatatablesRails
   module Datatable
     class SimpleSearch
 
+      TRUE_VALUE = 'true'
+
       def initialize(options = {})
         @options = options
       end