JS: Enhance isDomProperty to check for getAPropertyRead on DOM nodes

Author: Napalys

javascript/ql/lib/Expressions/DOMProperties.qll

@@ -10,4 +10,8 @@ predicate isDomProperty(string p) {
   exists(ExternalMemberDecl emd | emd.getName() = p |
     isDomRootType(emd.getDeclaringType().getASupertype*())
   )
+  or
+  exists(DataFlow::SourceNode domNode | isDomNode(domNode) |
+    p = domNode.getAPropertyRead().getPropertyName()
+  )
 }

javascript/ql/test/query-tests/Expressions/ExprHasNoEffect/ExprHasNoEffect.expected

@@ -1,5 +1,3 @@
-| dom.js:5:3:5:18 | box.offsetHeight | This expression has no effect. |
-| dom.js:11:5:11:40 | documen ... ntWidth | This expression has no effect. |
 | try.js:22:9:22:26 | x.ordinaryProperty | This expression has no effect. |
 | tst2.js:2:4:2:4 | 0 | This expression has no effect. |
 | tst.js:3:1:3:2 | 23 | This expression has no effect. |

javascript/ql/test/query-tests/Expressions/ExprHasNoEffect/dom.js

@@ -2,12 +2,12 @@ function f() {
   const box = document.getElementById('box');
   box.classList.remove('animate');
   // Force a reflow by reading layout property (side effect!)
-  box.offsetHeight; // $SPURIOUS:Alert
+  box.offsetHeight;
 
   try {
     console.log("Hello, world!");
   } catch (e) {
     // Reading this property also forces layout
-    document.documentElement.clientWidth; // $SPURIOUS:Alert
+    document.documentElement.clientWidth;
   }
 }