diff --git a/README.md b/README.md
index 27eb217..c8bb4a6 100644
--- a/README.md
+++ b/README.md
@@ -84,6 +84,7 @@ You may now send a Pull Request. Tests are automatically run on Pull Requests, s
 - Buttons conform to supported values.
 - Hats aren't 0 or diagonals.
 - No upstream official mappings are modified.
+- All mappings end with a comma.
 
 ### Formatting
 - The database is sorted by platform, then by name.
diff --git a/check.py b/check.py
index 35ec96c..5cbd2b4 100755
--- a/check.py
+++ b/check.py
@@ -73,6 +73,9 @@ class Mapping:
     }
 
     def __init__(self, mapping_string, line_number, add_missing_platform = False):
+        if not mapping_string.endswith(",\n") and not mapping_string.endswith(","):
+            raise ValueError("Mapping should end with comma (,)")
+
         self.guid = ""
         self.name = ""
         self.platform = ""
diff --git a/gamecontrollerdb.txt b/gamecontrollerdb.txt
index 899c698..4a0ad9d 100644
--- a/gamecontrollerdb.txt
+++ b/gamecontrollerdb.txt
@@ -170,7 +170,7 @@ xinput,XInput Controller,a:b0,b:b1,back:b6,dpdown:h0.4,dpleft:h0.8,dpright:h0.2,
 030000008f0e00001330000011010000,HuiJia SNES Controller,a:b4,b:b2,back:b16,dpdown:+a2,dpleft:-a0,dpright:+a0,dpup:-a2,leftshoulder:b12,rightshoulder:b14,start:b18,x:b6,y:b0,platform:Mac OS X,
 03000000830500006020000000010000,iBuffalo SNES Controller,a:b1,b:b0,back:b6,dpdown:+a1,dpleft:-a0,dpright:+a0,dpup:-a1,leftshoulder:b4,rightshoulder:b5,start:b7,x:b3,y:b2,platform:Mac OS X,
 03000000830500006020000000000000,iBuffalo USB 2-axis 8-button Gamepad,a:b1,b:b0,back:b6,leftshoulder:b4,leftx:a0,lefty:a1,rightshoulder:b5,start:b7,x:b3,y:b2,platform:Mac OS X,
-030000007e0500000620000001000000,Joy-Con (L),a:b0,b:b1,x:b2,y:b3,start:b8,leftstick:b10,leftshoulder:b4,rightshoulder:b5,-leftx:h0.8,+leftx:h0.2,-lefty:h0.1,+lefty:h0.4,platform:Mac OS X
+030000007e0500000620000001000000,Joy-Con (L),+leftx:h0.2,+lefty:h0.4,-leftx:h0.8,-lefty:h0.1,a:b0,b:b1,leftshoulder:b4,leftstick:b10,rightshoulder:b5,start:b8,x:b2,y:b3,platform:Mac OS X,
 030000006d04000016c2000000020000,Logitech Dual Action,a:b1,b:b2,back:b8,dpdown:h0.4,dpleft:h0.8,dpright:h0.2,dpup:h0.1,leftshoulder:b4,leftstick:b10,lefttrigger:b6,leftx:a0,lefty:a1,rightshoulder:b5,rightstick:b11,righttrigger:b7,rightx:a2,righty:a3,start:b9,x:b0,y:b3,platform:Mac OS X,
 030000006d04000016c2000000030000,Logitech Dual Action,a:b1,b:b2,back:b8,dpdown:h0.4,dpleft:h0.8,dpright:h0.2,dpup:h0.1,leftshoulder:b4,leftstick:b10,lefttrigger:b6,leftx:a0,lefty:a1,rightshoulder:b5,rightstick:b11,righttrigger:b7,rightx:a2,righty:a3,start:b9,x:b0,y:b3,platform:Mac OS X,
 030000006d04000016c2000014040000,Logitech Dual Action,a:b1,b:b2,back:b8,dpdown:h0.4,dpleft:h0.8,dpright:h0.2,dpup:h0.1,leftshoulder:b4,leftstick:b10,lefttrigger:b6,leftx:a0,lefty:a1,rightshoulder:b5,rightstick:b11,righttrigger:b7,rightx:a2,righty:a3,start:b9,x:b0,y:b3,platform:Mac OS X,