diff --git a/lib/linguist/languages.yml b/lib/linguist/languages.yml
index 61e790ba..91224b22 100644
--- a/lib/linguist/languages.yml
+++ b/lib/linguist/languages.yml
@@ -216,9 +216,9 @@ CoffeeScript:
   ace_mode: coffee
   aliases:
   - coffee
+  primary_extension: .coffee
   extensions:
   - ._coffee
-  - .coffee
   filenames:
   - Cakefile
 
diff --git a/test/test_language.rb b/test/test_language.rb
index 90a5e26a..a214adc3 100644
--- a/test/test_language.rb
+++ b/test/test_language.rb
@@ -337,6 +337,8 @@ class TestLanguage < Test::Unit::TestCase
     assert_equal '.pl', Language['Perl'].primary_extension
     assert_equal '.py', Language['Python'].primary_extension
     assert_equal '.rb', Language['Ruby'].primary_extension
+    assert_equal '.js', Language['JavaScript'].primary_extension
+    assert_equal '.coffee', Language['CoffeeScript'].primary_extension
 
     # This is a nasty requirement, but theres some code in GitHub that
     # expects this. Really want to drop this.