如何确认一个循环中所有可观察对象的执行 - （Angular 2）？答案

【问题标题】：How can I to confirm the execution of all observables in a cycle - (Angular 2)?如何确认一个循环中所有可观察对象的执行 - （Angular 2）？
【发布时间】：2016-08-08 02:04:25
【问题描述】：

在 Angular 2 中，我如何确认“n”个“observables”何时完成：

  ...
  for (var i = 1; i <= this.quantity; i++) {
    description = this.prefix.trim() + ' ' + i.toString();
    point = new PointModel(description, 'A', this.locationModel.id);
    this.point.create(<PointModel>point)
      .subscribe(
      pointModel => {
        Materialize.toast('Se ha guardado el punto \"' + pointModel.description + '\"', 2000);
      },
      error => {
        Materialize.toast('Se ha generado un error: \"' + error + '\"', 2000);
      }
      );
  }
  ...

谢谢！

【问题讨论】：

标签： typescript angular loopback

【解决方案1】：

应该是这样的：

//create and fill points array
var points:PointModel[] = [];
for (var i = 1; i <= this.quantity; i++) {
  description = this.prefix.trim() + ' ' + i.toString();
  points.push(new PointModel(description, 'A', this.locationModel.id));
}

Observable.from(points).flatMap(point=>{this.point.create(<PointModel>point)})
.subscribe(
  pointModel => {
    Materialize.toast('Se ha guardado el punto \"' + pointModel.description + '\"', 2000);
  },
  error => {
    Materialize.toast('Se ha generado un error: \"' + error + '\"', 2000);
  },
  () => {
     Materialize.toast('All points have been created!', 2000);
  }      
  );

【讨论】：

【解决方案2】：

我的最终代码是：

  for (var i = 1; i <= this.quantity; i++) {
    description = this.prefix.trim() + ' ' + i.toString();
    points.push(new PointModel(description, 'A', this.locationModel.id));
  }

  Observable.fromArray(points).flatMap( //'fromArray' is deprecated, instead use 'from'
    point => {
      return this.point.create(<PointModel>point); //the return was the key here...
    }
  )
    .subscribe(
    pointModel => {
      Materialize.toast('Se ha guardado el punto \"' + pointModel.description + '\"', 2000);
    },
    error => {
      Materialize.toast('Se ha generado un error: \"' + error + '\"', 2000);
    },
    () => {
      this.loadPointsFromModelId(this.pointModel.id);
    }
    );

【讨论】：