Merge pull request #5471 from Microsoft/jsFileCompilation

Compilation of Js Files

src/compiler/types.ts

@@ -2360,6 +2360,7 @@ namespace ts {
         noImplicitReturns?: boolean;
         noFallthroughCasesInSwitch?: boolean;
         forceConsistentCasingInFileNames?: boolean;
+        allowJs?: boolean;
         /* @internal */ stripInternal?: boolean;
 
         // Skip checking lib.d.ts to help speed up tests.