Merge pull request #3192 from asger-semmle/js/missing-await-not-delete

Approved by esbena

javascript/ql/src/Expressions/MissingAwait.ql

@@ -45,7 +45,8 @@ predicate isBadPromiseContext(Expr expr) {
   or
   exists(UnaryExpr e |
     expr = e.getOperand() and
-    not e instanceof VoidExpr
+    not e instanceof VoidExpr and
+    not e instanceof DeleteExpr
   )
   or
   expr = any(UpdateExpr e).getOperand()

javascript/ql/test/query-tests/Expressions/MissingAwait/tsTest.ts

@@ -0,0 +1,5 @@
+declare let cache: { [x: string]: Promise<any> };
+
+function deleteCache(x: string) {
+    delete cache[x]; // OK
+}

javascript/ql/test/query-tests/Expressions/MissingAwait/tsconfig.json

@@ -0,0 +1,3 @@
+{
+    "include": ["."]
+}