对象数据过滤的Rxjs数组

Question

我正在尝试使用selectedProject activities: Activity[]过滤ngrx状态。selectedProject的密钥是用来获得可观察到的[{$key, true}, ...]的。如何过滤activities: Activity[]状态呢?对于曾经使用过rxjs的人来说，这可能是一个非常简单的问题。

let obs: Observable<Project> = this.appstore.select('selectedProject');
let actskeys: FirebaseListObservable<any[]>;
    obs.subscribe(val => 
      {
        id = val.$key;
        actskeys = this.db.list(`/projectActs/${id}`);// This returns [{$key: true},{$key: true},...]
        this.appstore.select('activities'); // I want to filter this store using the actkeys, $key.
                }
    );

我的try非工作代码

 getActsByCourseId(): Observable<Activity[]>{
    let id: string;
    let actskeys: FirebaseListObservable<any[]>;
    let obs: Observable<Project> = this.appstore.select('selectedProject');
    let acts = this.appstore.select('activities')
    let filteredActs: Activity[] = [];
    obs.subscribe(val => 
                {
                    id = val.$key;
                    actskeys = this.db.list(`/projectActs/${id}`);
                    actskeys.subscribe(val => {val.forEach(bb => 
                        acts
                        .filter((res: Activity[]) => res && res.length > 0 )
                        .map((res: Activity[]) => res.filter(val => val.$key === bb.$key))
                        .subscribe(res => console.log(res))
                        );
                        this.appstore.dispatch({ type: LOAD_Activities, payload: filteredActs});                         
                    }
                    )                      
                }
    );
    return this.appstore.select('activities');
}

更新代码:我已经尝试过combineLatest

let selectedProject$ = this.appstore.select<Project>('selectedProject');
    let activities$ = this.appstore.select<Activity[]>('activities');
    let actskeys$: FirebaseListObservable<any[]>;
    let filteredActs: Observable<any[]> ;
    selectedProject$
        //.withLatestFrom(actskeys$, activities$)
            .map((selectedProject) => {
                    id = selectedProject.$key;
                    return actskeys$ = this.db.list(`/projectActs/${id}`);
    // filter here your activities ...
   })
   .subscribe(res => {
     filteredActs = this.getProjectActs(res);
   });
   filteredActs.subscribe(
                        res => {
                        console.log(res);
                        //  this.appstore.dispatch({ type: LOAD_Activities,     
                            payload: res});
                         }
                     );
    return this.appstore.select('activities');
    }

    getProjectActs(actskeys$:FirebaseListObservable<any[]>):   
    Observable<any[]> {
    let activities$ = this.appstore.select<Activity[]>('activities');
    return  Observable.combineLatest(activities$, actskeys$, (acts, keys) =>    
                        {
                         return keys.map(key => {
                             acts.filter(act => act.$key === key.$key);
                        })
                    })
    };

我正在从控制台获取[undefined, undefined]。

Answer 1

不能完全理解你在做什么，但你可以试一试：

let selectedProject$ = this.appstore.select<Project>('selectedProject');
let activities$ = this.appstore.select<Activities>('activities');
let actskeys$: FirebaseListObservable<any[]>;

selectedProject$
    .withLatestFrom(actskeys$, activities$)
    .map([selectedProject, actskeys, activities] => {
        id = selectedProject.$key;
        actskeys = this.db.list(`/projectActs/${id}`);

        // filter here your activities ...
    })
    .subscribe();