diff --git a/lib/rouge/lexers/tsx.rb b/lib/rouge/lexers/tsx.rb
index 043a526f23..c735703de6 100644
--- a/lib/rouge/lexers/tsx.rb
+++ b/lib/rouge/lexers/tsx.rb
@@ -7,7 +7,7 @@ module Lexers
     load_lexer 'typescript/common.rb'
 
     class TSX < JSX
-      include TypescriptCommon
+      extend TypescriptCommon
 
       title 'TypeScript'
       desc 'tsx'
diff --git a/lib/rouge/lexers/typescript.rb b/lib/rouge/lexers/typescript.rb
index 5a4283fd59..5719c9f787 100644
--- a/lib/rouge/lexers/typescript.rb
+++ b/lib/rouge/lexers/typescript.rb
@@ -7,7 +7,7 @@ module Lexers
     load_lexer 'typescript/common.rb'
 
     class Typescript < Javascript
-      include TypescriptCommon
+      extend TypescriptCommon
 
       title "TypeScript"
       desc "TypeScript, a superset of JavaScript"
diff --git a/lib/rouge/lexers/typescript/common.rb b/lib/rouge/lexers/typescript/common.rb
index 7d161ff05f..8cb5026323 100644
--- a/lib/rouge/lexers/typescript/common.rb
+++ b/lib/rouge/lexers/typescript/common.rb
@@ -4,27 +4,27 @@
 module Rouge
   module Lexers
     module TypescriptCommon
-      def self.keywords
+      def keywords
         @keywords ||= super + Set.new(%w(
           is namespace static private protected public
           implements readonly
         ))
       end
 
-      def self.declarations
+      def declarations
         @declarations ||= super + Set.new(%w(
           type abstract
         ))
       end
 
-      def self.reserved
+      def reserved
         @reserved ||= super + Set.new(%w(
           string any void number namespace module
           declare default interface keyof
         ))
       end
 
-      def self.builtins
+      def builtins
         @builtins ||= super + %w(
           Pick Partial Readonly Record
         )