JS: address comments

Author: asger-semmle

javascript/ql/src/semmle/javascript/dataflow/Nodes.qll

@@ -488,6 +488,8 @@ DataFlow::SourceNode moduleMember(string path, string m) {
  *   method: function() {}
  * });
  * ```
+ *
+ * Additional patterns can be recognized as class nodes, by extending `DataFlow::ClassNode::Range`.
  */
 class ClassNode extends DataFlow::SourceNode {
   ClassNode::Range impl;
@@ -510,24 +512,28 @@ class ClassNode extends DataFlow::SourceNode {
   FunctionNode getConstructor() { result = impl.getConstructor() }
 
   /**
-   * Gets an instance method with the given name, if any.
+   * Gets an instance method declared in this class, with the given name, if any.
+   *
+   * Does not include methods from superclasses.
    */
   FunctionNode getInstanceMethod(string name) { result = impl.getInstanceMethod(name) }
 
   /**
-   * Gets an instance method of this class.
+   * Gets an instance method declared in this class.
    *
    * The constructor is not considered an instance method.
+   *
+   * Does not include methods from superclasses.
    */
   FunctionNode getAnInstanceMethod() { result = impl.getAnInstanceMethod() }
 
   /**
-   * Gets the static method of this class with the given name.
+   * Gets the static method declared in this class with the given name.
    */
   FunctionNode getStaticMethod(string name) { result = impl.getStaticMethod(name) }
 
   /**
-   * Gets a static method of this class.
+   * Gets a static method declared in this class.
    *
    * The constructor is not considered a static method.
    */
@@ -619,12 +625,12 @@ module ClassNode {
         result = method.getBody().flow()
       )
       or
-      result = getAPropertyWrite(name).getRhs().getALocalSource()
+      result = getAPropertySource(name)
     }
 
     override FunctionNode getAStaticMethod() {
       exists(MethodDeclaration method |
-        method = astNode.(ClassDefinition).getAMethod() and
+        method = astNode.getAMethod() and
         method.isStatic() and
         result = method.getBody().flow()
       )
@@ -646,15 +652,15 @@ module ClassNode {
     override FunctionNode getConstructor() { result = this }
 
     override FunctionNode getInstanceMethod(string name) {
-      result = getAPrototypeReference().getAPropertyWrite(name).getRhs().getALocalSource()
+      result = getAPrototypeReference().getAPropertySource(name)
     }
 
     override FunctionNode getAnInstanceMethod() {
       result = getAPrototypeReference().getAPropertyWrite().getRhs().getALocalSource()
     }
 
     override FunctionNode getStaticMethod(string name) {
-      result = getAPropertyWrite(name).getRhs().getALocalSource()
+      result = getAPropertySource(name)
     }
 
     override FunctionNode getAStaticMethod() {