typescript - 尝试使用angularfire以角度加入一对多Firebase文件(Trying to join one-to-many firebase documents in angular using angularfire)

Question

I know this has been asked before but I can't figure out my scenario from the typical answers provided.

(我知道以前已经有人问过这个问题，但是我无法从提供的典型答案中弄清楚我的情况。)

In my app I have firebase collection called objectives and a tasks collection that have a one to many relationship.

(在我的应用程序中，我有称为目标的firebase集合和具有一对多关系的任务集合。)

Each objective has a tasks array (filled with the ID's of the tasks) and each task has an objectiveId.

(每个目标都有一个任务数组（填充有任务的ID），每个任务都有一个ObjectiveId。)

I would like to join these so when I make a snapshotChanges() call to get all objectives I would like to return an array of objectives with tasks objects nested in.

(我想加入这些对象，所以当我进行snapshotChanges（）调用以获取所有目标时，我想返回一个嵌套了任务对象的目标数组。)

I have this code and I know it does not work cuz I can't return something in an observable but I was wondering how would I use RxJS operators in this case?

(我有这段代码，我知道它不起作用，因为我无法以可观察的方式返回某些内容，但是我想知道在这种情况下如何使用RxJS运算符？)

loadObjectives() {
 return this.objectivesCollection.snapshotChanges().pipe(
  map(actions => {
    return actions.map(_ => {
      const id = _.payload.doc.id;
      const data = _.payload.doc.data();
      const tasks = this.afs
        .collection<Task>("tasks", ref =>
          ref.where("objectiveId", "==", id)
        )
        .valueChanges().subscribe( tasks => {
          return new Objective(id, data.title, tasks);
        });
    });
  }),
  tap(objectives => {
    this._objectives.next(objectives);
  })
);}

  ask by Faisal Choura translate from so

Answer 1

等待大神答复