Old habits die hard: !== instead of !=.

Author: gkellogg

lib/graphTypes.js

@@ -79,7 +79,7 @@ api.isGraph = v => {
   // 3. It may have '@id' or '@index'
   return types.isObject(v) &&
     '@graph' in v &&
-    Object.keys(v).filter(key => key != '@id' && key != '@index').length === 1;
+    Object.keys(v).filter(key => key !== '@id' && key !== '@index').length === 1;
 };
 
 /**