title: NGRX Effect Property 'type' is missing in type Observable<any[]>
body: <p>I am upgrading my app from angular from v6 to v7. 
  I am also upgrade the Typescript version to 2.7.2 to 3.1.6</p>
  
  <p>My problem is when I typescript complaints my ngrx effect has property 'type' missing. This is not occur in 2.7.2</p>
  
  <p>It just maybe I'm not understand how the types work. Could you please show me what I am doing wrong here? </p>
  
  <pre class="lang-js prettyprint-override"><code>    @Effect()
      login(): Observable&lt;Action&gt; {
          return this.actions$.pipe(
              ofType(AuthActionTypes.LOGIN),
              switchMap((action: LoginAction) =&gt; {
                  const username = action.username;
                  const password = action.password;
                  return this.authenticationService.login(username, password)
                      .pipe(
                          switchMap(token =&gt; {
                              return [
                                  new SetTokenAction({token: token}),
                              ];
                          }),
                          catchError(err =&gt; {
                              return [new LoginErrorAction((err))];
                          })
                      );
              })
          );
      }
  </code></pre>
  
  <p>This is the result of the code </p>
  
  <blockquote>
    <p>TS2322:
    Type 'Observable>' is not assignable to type 'Observable'.
      Type 'Observable' is not assignable to type 'Action'.
        Property 'type' is missing in type 'Observable'.</p>
  </blockquote>