如何 return Observable Array 而不是订阅？

Question

如何使这个 forkJoin return 成为可观察数组而不是订阅？

connect(): Observable<any[]> {
this.userId = this.authService.userId;
this.habits$ = this.habitService.fetchAllById(this.userId);
this.status$ = this.statusService.fetchAll();
this.joined$ = forkJoin([
  this.habits$,
  this.status$
]).subscribe(([habits, statuses]) => {
  this.joined = habits.map(habit => ({
    ...statuses.find(t => t.habitId === habit.habitId),
    ...habits
  }));
});
return this.joined$;

}

目前我的变量定义如下：

export class HabitDataSource extends DataSource<any> {

  userId: Pick<User, 'id'>;
  habits$: Observable<Habit[]>;
  status$: Observable<Status[]>;
  joined$: Subscription;
  joined: any[];

但是 connect() 方法需要一个 Observable-Array。

Answer 1

How can I make this forkJoin return an observable-array instead of a subscription?

forkJoin 做 return 数组。你得到 Subscription 的原因是因为你正在调用 .subscribe().

您可以使用 map 运算符，而不是在订阅中执行映射逻辑：

connect(): Observable<any[]> {
  this.userId  = this.authService.userId;
  this.habits$ = this.habitService.fetchAllById(this.userId);
  this.status$ = this.statusService.fetchAll();
  
  return forkJoin([this.habits$, this.status$]).pipe(
    map(([habits, statuses]) =>
      habits.map(habit => ({
        ...habit,
        status: statuses.find(s => s.habitId === habit.habitId)
      }))
    )
  );
}

如何 return Observable Array 而不是订阅？

How to return an Observable Array instead of a subscription?

javascript

arrays

observable

typescript

angular