Opposite of splitters
Combines multiple actions back down to one
Useful when flow needs to wait for actions to complete before next step
// Effect aggregators@Effect()aggregator = this.actions$.pipe(ofType<LoadUserById>(UserActionTypes.LoadUserById),flatMap(a =>zip(this.actions$.pipe(ofType<LoadUserByIdSuccess>(UserActionTypes.LoadUserByIdSuccess),first(t => t.payload.id === a.payload.id)),this.actions$.pipe(ofType<Logged>(LogActionTypes.Logged),first(t => t.payload.id === a.payload.id)))),map(pair => new LoadAdminUserSuccess()));