- Change back, add missing !

Author: wesleycho

src/ng/compile.js

@@ -781,7 +781,7 @@ function $CompileProvider($provide, $$sanitizeUriProvider) {
 
   function assertValidDirectiveName(name) {
     var letter = name.charAt(0);
-    if (letter && letter !== lowercase(letter)) {
+    if (!letter || letter !== lowercase(letter)) {
       throw ngMinErr('badname', "Directive name '{0}' is invalid. The first letter of a directive must be a lowercase letter");
     }
     return name;