You only need to use the toPayload operator if you’ve created your actions with payloads:

import { action, payload } from "ts-action";
export const Foo = action("FOO", payload<{ name: string }>());

Then your effect would look like this:

@Effect() fooAction$ = this.actions$
  .ofType(Foo)
  .toPayload()
  .switchMap(payload => ...);

Early versions of NgRx put the action properties into a payload property, but it no longer does this. However, the structure of your actions is up to you. If you create them with payloads, toPayload is useful. Otherwise, it isn’t,