请问这里的store.select()的内容是啥返回啥?

 @Effect()
  shipperSignUpEffect$ = this.actions$
    .ofType<signUpActions.ShipperSignUp>(signUpActions.ShipperSignUpActionTypes.ShipperSignUpAction) 
    .pipe(
      map(action => action.payload), 
      withLatestFrom(this.store.select(fromAuth.getSignUpToken)),
      exhaustMap(([account, token]) =>
        this.shipperService
          .shipperSignup(account.shipper, token)
          .pipe(
            map(rsp => new signUpActions.ShipperSignUpSuccess()),
            catchError(error =>
              of(new signUpActions.ShipperSignUpFailed(error))
            )
          )
      )
    );
    ```
    请问这里的store.select()的用处是啥？里面的参数是啥？谢谢！

map(rsp => new signUpActions.ShipperSignUpSuccess()),

https://github.com/berwin/Blog/issues/4