Angular2观测 - 如何等待所有功能在一个循环中继续之前结束通话？ [英] Angular2 Observable - how to wait for all function calls in a loop to end before proceeding?

问题描述

我想通过迁移目前写在Angular1的应用程序，以提高我Angular2知识

I am trying to improve my knowledge of Angular2 by migrating an application currently written in Angular1

在一个特别的功能已难倒我。我试图复制一个特征，其中一个调用函数等待继续，直到它被调用函数完成承诺的循环。在角一个功能我打电话基本上是这样的：

One feature in particular has me stumped. I am trying to replicate a feature where a calling function waits to proceed until the function it is calling has completed a loop of promises. In angular one the function I am calling looks basically like this:

.       this.processStuff = function( inputarray, parentnodeid ) {
.   
.           var promises = [];
.   
.           var _self = this;
.   
.           angular.forEach( inputarray , function( nodeid ) {
.   
.               switch ( parentnodeid )
.               {
.                   case ‘AAA’ : var component = _self.doMoreStuff( nodeid, parentnodeid ); break;
.                   case ‘BBB’ : var component = _self.doMoreStuff( nodeid, parentnodeid ); break;
.                   case ‘CCC’ : var component = _self.doMoreStuff( nodeid, parentnodeid ); break;
.                   default    : var component = null;
.               }
.   
.               promises.push( component );
.   
.           });
.   
.           return $q.all(promises);
.       }; 

它包含一个foreach循环调用另一个函数（doMoreStuff）也返回一个承诺，其存储阵列中的所有返回的承诺。

It contains a forEach loop that calls another function (doMoreStuff) that also returns a promise and it stores all those returned promises in an array.

通过Angular1，当我打电话processStuff在另一个函数，我可以算系统等到processStuff在当时块进入code之前完成。 IE浏览器：

With Angular1, when I call processStuff in another function, I could count on the system waiting until processStuff completed before entering into the code in the then block. IE:

. service.processStuff( arraying, parentidarg )
.        .then(function( data ) {
.              . . . 

processStuff的调用者等待所有doMoreStuff调用来完成，直到processStuff的调用者进入其当时块。

The caller of processStuff waits for all doMoreStuff invocations to complete until the caller of processStuff enters into its then block.

我不确定如何与Angular2和观测量来实现这一目标。我可以从这些帖子，为了模仿承诺，观测量基本上只使用订阅，而不是再看看：

I am unsure of how to achieve this with Angular2 and Observables. I can see from these posts that to mimic promises, Observables basically just use subscribe instead of then:

角的1.x $ Q角到2.0测试版

但我怎么等待在foreach循环中所有调用完成之前，我的系统可以继续？

But how do I wait for all invocations in the forEach loop to complete before my system can proceed?

大大预先感谢您的帮助，您可以分享。

Thank you greatly in advance for help you can share.

推荐答案

我一直forkJoin这样

I have been doing this with forkJoin

import {Observable} from 'rxjs/Observable';

Observable.forkJoin(
  this.http.get('./friends.json').map((res: Response) => res.json()),
  this.http.get('./customer.json').map((res: Response) => res.json())
).subscribe(res => this.combined = {friends:res[0].friends, customer:res[1]});

更多的一些信息在这里： http://www.syntaxsuccess.com/viewarticle /angular-2.0-and-http

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