forkjoin没有结果

问题描述

我正在使用forkJoin合并两个Firebase请求的结果

I'm using forkJoin to combine the results of two firebase requests

这两个请求都已完成并在控制台中登录，但是forkJoin本身的map函数不会触发，因此没有结果返回给应用程序

Both requests complete and log within the console, but the map function for the forkJoin itself does not fire and hence no results are returned to the application

public initGroup(groupname, username){
  console.log(groupname, username)//This logs
  return Observable.forkJoin([
      this.getGroup(groupname, username),
      this.groupMembers(username, groupname),
    ])
    .map((data)=>{
      console.log(data)//This does not log
      this.group = data;
      return this.group
    })
}

对于单个功能:

public getGroup(groupname, username){
  return (this._af.database.object('/groups/'+groupname) as FirebaseObjectObservable<any>)
      .map((group)=>{
       console.log(group)//This logs
       return group
  })

}
 public groupMembers(username, groupname){
  return  this.afService.getUserItems(groupname)
  .map((users:UserInfo[])=>{
    console.log(users)//This logs
    return users
  })
}

我在组件内订阅

let conn = this.groupService.initGroup(groupname, username)
                  .subscribe((data)=>{
                  console.log(data)//Does not log
                  ......
                })

推荐答案

事实证明forkJoin不适用于Firebase可观察对象，

It turns out forkJoin just doesn't work with firebase observables,

当我更新到

public initGroup(groupname, username){
  return Observable.combineLatest([
      this.getGroup(groupname, username),
      this.groupMembers(username, groupname)

  ])
    .map((data)=>{
      console.log(data)//This now logs
      this.group = data;
      return this.group
    })


}

combineLatest使它按预期工作

combineLatest made it work as expected

这篇关于forkjoin没有结果的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！