add support for the new using keyword in TypeScript

Author: erik-krogh

javascript/extractor/src/com/semmle/ts/extractor/TypeScriptASTConverter.java

@@ -2683,10 +2683,13 @@ private boolean hasKind(JsonElement node, String kind) {
   }
 
   /**
-   * Gets the declaration kind of the given node, which is one of {@code "var"}, {@code "let"} or
-   * {@code "const"}.
+   * Gets the declaration kind of the given node, which is one of {@code "var"}, {@code "let"}, 
+   * {@code "const"}, or {@code "using"}.
    */
   private String getDeclarationKind(JsonObject declarationList) {
+    if (hasFlag(declarationList, "Using")) {
+      return "using";
+    }
     return declarationList.get("$declarationKind").getAsString();
   }
 }

javascript/ql/test/library-tests/TypeScript/BindingPattern/VarDecl.expected

@@ -1,3 +1,12 @@
+consts
+| tst.tsx:2:3:2:26 | const { ...  } = o; |
+| tst.tsx:9:5:9:26 | const b ... efined; |
+usings
+| tst.tsx:7:5:7:28 | using f ... as any; |
+#select
 | tst.tsx:1:10:1:10 | f |
 | tst.tsx:1:12:1:12 | o |
 | tst.tsx:2:14:2:14 | v |
+| tst.tsx:6:10:6:10 | v |
+| tst.tsx:7:11:7:13 | foo |
+| tst.tsx:9:11:9:13 | bar |

javascript/ql/test/library-tests/TypeScript/BindingPattern/VarDecl.ql

@@ -2,3 +2,7 @@ import javascript
 
 from VarDecl decl
 select decl
+
+query ConstDeclStmt consts() { any() }
+
+query UsingDeclStmt usings() { any() }

javascript/ql/test/library-tests/TypeScript/BindingPattern/tst.tsx

@@ -2,3 +2,9 @@ function f(o) {
   const { p: v = [] } = o;
   return v;
 }
+
+function v() {
+    using foo = null as any;
+
+    const bar = undefined;
+}