链可观察 [英] Chain Observable

问题描述

我对可观察的链接有疑问.

I have a problem with observable chaining.

我的目标是获得以下结果: {分页，Process []}和Process = {.....，变量[]}

My goal is to have this result : {Pagination, Process[]} and Process = { ....., Variables[]}

我正在调用返回对象 {Pagination，Process []} 的服务，但是 Process 中的变量为空.

I'm calling a service which return an object {Pagination, Process[]} but Variables in Process are empty.

因此，我需要使用变量"属性来完成过程对象.

So i need to complete the process object with Variables properties.

我愿意:

this.processesService.getData().subscribe(() => {   // data  });
getData: Observable<any> {
   let processesResult = fromPromise( .... );

    return processesResult.pipe(

      map( (result) => { <= result is list of process without variables
        let entries = new Array();

        result.entries.map( **process** =>  {
          result.entries = entries;
          this.getCompleteProcess(**process.id**).subscribe((_process) => {
            entries.push(_process) <-- the process with Variables[] for enrich result map
          })
          return result.entries;
        })
      })
    );
}

您能帮我解决我的问题吗?我需要等待 this.getCompleteProcess 填充父对象并返回完整的结果

Can you help me to resolve my problem ? i need to wait this.getCompleteProcess to populate parent object and return a complete result

谢谢

推荐答案

我认为rxjs中可以尝试一些运算符(例如forkJoin，concatMap).否则，您还可以使用Observable.create.例如，

I think there are a few operators in rxjs that you could try out (e.g. forkJoin, concatMap). Otherwise what you could also do is to use the Observable.create. For example,

getData: Observable<any> {
    return Observable.create( (obs) => {
      let processesResult = fromPromise( .... ).subscribe(
      (result) => { <= result is list of process
        let entries = new Array();
        let obsArr = [];
        result.entries.forEach( **process** =>  {
          result.entries = entries;
          obsArr.push(this.getCompleteProcess(**process.id**).pipe(map((_process) => {
            entries.push(_process) <-- the process is complete and i need it to enrich result map
          });
          forkJoin(...obsArr).subscribe( ([]) => {
               obs.next(result.entries) => EMIT RESPONSE HERE
          } );
        })
      })
    );
}

请注意-我尚未对此进行编译或测试.但基本上，这个想法是创建一个可包装的可观察对象，一旦所有逻辑完成，它就会发出一个值.希望这会有所帮助.

Please note - I have not compiled or tested this. But basically, the idea is to create a wrapping observable which emits a value once all the logic is done. Hope this helps.

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