在Angular2中，如何在填充其他对象属性之前不调用方法

使用Angular2，我试图在填充“itemU”的属性之前不调用setGroups（）方法。属性由名为setMyData（）的方法中的api调用填充

填充这些属性后，如何调用此.setGroups（）？

//inside of ngOnInit()
    this.myService.getMyData(this.userId)
            .takeUntil(this.ngUnsubscribe)
            .subscribe(user => this.setMyData(user));

      if(this.itemU.gr1 || this.itemU.gr2 || this.itemU.gr3){
        this.setGroups();
      }
//properties are getting set after the break point passes the if(this.itemU.gr1..

setMyData通过api调用填充this.itemU.gr1 | | this.itemU.gr2 | | this.itemU.gr1属性

//outside of ngOnInit()
  setMyData(user: models.ListOfResponse) {
    this.itemU = objectSample[0];

   //sets gr1 
   this.myService.get1(this.u.id )
      .subscribe(access => this.setA(access));  

   //sets gr2
    this.myService.get2(this.u.key, true)
      .subscribe(
        groups => this.hasPerms(groups, false)
        ,error => this.isUnavailable = true
      );                   

   //set gr3
    this.myService.get2(this.u.key, true)
      .subscribe(
        groups => this.hasPerms(groups, true)
        ,error => this.isUnavailable = false
      ); 
  }

下面是“hasPerms（）”方法的示例：

---

我会在get2和3上执行Observable.forkJoin，然后执行setGroups（）。不过，这个.setA似乎必须在之前执行。这就是为什么forkJoin在get1中

setMyData(user: models.ListOfResponse) {
  this.itemU = objectSample[0];

  //sets gr1 
  this.myService.get1(this.u.id )
    .subscribe(access => {
      this.setA(access)

      Rx.Observable.forkJoin(
        this.myService.get2(this.u.key, true),
        this.myService.get2(this.u.key, true)
      )      
      .subscribe(
        groups => {
          // here groups is an array so execute this.hasPerms(groups, false) in a loop
          // then call this.setGroups(); as everything is completed now
        }
        ,error => this.isUnavailable = true
      );                   
    });  

}

您也可以使用rxjs的行为主体：

itemUPopulated$ = new BehaviorSubject(false); 

this.myService.getMyData(this.userId)
        .takeUntil(this.ngUnsubscribe)
        .subscribe(user => this.setMyData(user));

itemUPopulated$.subscribe(populated => {
  if (populated) {
    this.setGroups();
  }
});

现在，在代码的后面，每当填充itemU时，只要执行

itemUPopulated$.next(true);

可能在

hasPerms1（）函数中：

hasPerms1(groups: models.Stuff[], isTrue: boolean) {
  if (isTrue) {
    this.itemU.gr2 = groups;
    itemUPopulated$.next(true);
  }
  else { 
    this.itemU.gr3 = "";
  }
}

hasPerms1(groups: models.Stuff[], isTrue: boolean) {
  if (isTrue) {
    this.itemU.gr2 = groups;
    itemUPopulated$.next(true);
  }
  else { 
    this.itemU.gr3 = "";
  }
}