fix(typings): repair broken typechecks

We had the typechecker disabled by accident, and many problems snuck in

Fixes #4507

Closes #4508

modules/examples/src/web_workers/message_broker/index.ts

@@ -10,9 +10,9 @@ document.getElementById("send_echo")
       var val = (<HTMLInputElement>document.getElementById("echo_input")).value;
       // TODO(jteplitz602): Replace default constructors with real constructors
       // once they're in the .d.ts file (#3926)
-      var args = new UiArguments();
+      var args = new UiArguments("echo");
       args.method = "echo";
-      var fnArg = new FnArg();
+      var fnArg = new FnArg(val, PRIMITIVE);
       fnArg.value = val;
       fnArg.type = PRIMITIVE;
       args.args = [fnArg];