QL code and tests for C#/C++/JavaScript.

javascript/ql/src/Declarations/TooManyParameters.ql

@@ -0,0 +1,20 @@
+/**
+ * @name Function with too many parameters
+ * @description Functions with many parameters are hard to read and hard to use.
+ * @kind problem
+ * @problem.severity recommendation
+ * @id js/too-many-parameters
+ * @tags testability
+ *       readability
+ * @precision high
+ */
+
+import javascript
+import semmle.javascript.RestrictedLocations
+
+from Function f
+where not f.inExternsFile() and
+      f.getNumParameter() > 7 and
+      // exclude AMD modules
+      not exists (AMDModuleDefinition m | f = m.getFactoryNode().(DataFlow::FunctionNode).getAstNode())
+select (FirstLineOf)f, capitalize(f.describe()) + " has too many parameters (" + f.getNumParameter() + ")."