add support for destructuring object exports in getAnExportedValue

Author: erik-krogh

javascript/ql/src/semmle/javascript/ES2015Modules.qll

@@ -395,6 +395,13 @@ class ExportNamedDeclaration extends ExportDeclaration, @export_named_declaratio
       result = DataFlow::valueNode(d.getSource())
     )
     or
+    exists(ObjectPattern obj | obj = getOperand().(DeclStmt).getADecl().getBindingPattern() |
+      exists(DataFlow::PropRead read | read = result |
+        read.getBase() = obj.flow() and
+        name = read.getPropertyName()
+      )
+    )
+    or
     exists(ExportSpecifier spec | spec = getASpecifier() and name = spec.getExportedName() |
       not exists(getImportedPath()) and result = DataFlow::valueNode(spec.getLocal())
       or

javascript/ql/test/library-tests/Modules/tests.expected

@@ -71,6 +71,7 @@ test_Imports
 test_Module_exports
 | a.js:1:1:5:32 | <toplevel> | default | a.js:1:16:3:1 | functio ... n 23;\\n} |
 | a.js:1:1:5:32 | <toplevel> | x | a.js:5:18:5:20 | f() |
+| a.js:1:1:5:32 | <toplevel> | y | a.js:5:25:5:25 | y |
 | b.js:1:1:8:0 | <toplevel> | f2 | a.js:1:16:3:1 | functio ... n 23;\\n} |
 | b.js:1:1:8:0 | <toplevel> | g | b.js:5:10:5:10 | f |
 | e.js:1:1:4:0 | <toplevel> | g | a.js:1:16:3:1 | functio ... n 23;\\n} |
@@ -135,6 +136,7 @@ test_getLocalName
 test_getSourceNode
 | a.js:1:1:3:1 | export  ... n 23;\\n} | default | a.js:1:16:3:1 | functio ... n 23;\\n} |
 | a.js:5:1:5:32 | export  ...  } = o; | x | a.js:5:18:5:20 | f() |
+| a.js:5:1:5:32 | export  ...  } = o; | y | a.js:5:25:5:25 | y |
 | b.js:5:1:5:18 | export { f as g }; | g | b.js:5:10:5:10 | f |
 | b.js:7:1:7:21 | export  ...  './a'; | f2 | a.js:1:16:3:1 | functio ... n 23;\\n} |
 | e.js:2:1:2:16 | export { x, y }; | x | e.js:2:10:2:10 | x |