angular2- Observable getting data out of order

Question

So I am using a getAll to get all of a school's Virtual Hosts, which comes back as a list of ID's (id's of the Virtual Hosts). Then, in order to get the data of the Virtual Hosts, I must call another get on each of the ID's. I do this through a for loop like so--

 this.apiService.findAll("virtualhosts/deltest") .subscribe((data) => { this.data = data.docs[0] error => console.log(error) for (let i = 0; i < this.data.VirtualHosts.length; i++) { this.apiService.findVH(this.data.VirtualHosts[i]) .subscribe((data) => { this.data = data.docs[0] this.jsonData = this.jsonData.concat(this.data) }) } });

The problem is, the apiService.findVH does not call the get in order of the ID's given by the apiService.findAll. Every time it gets called, it doesn't compute the ID's in order of the list (hence the indices of this.data.VirtualHosts[i] is different) How can I make the findVH (get call) call the indices in order?

Hitmands · Accepted Answer · 2017-07-07 13:43:28Z

2

You can map an observable:

this .apiService .findAll("virtualhosts/deltest") .flatMap(data => this.apiService.findVH(data.VirtualHosts)) .subscribe(/* whatever you want */) ;

edited Jul 7, 2017 at 13:43

answered Jul 7, 2017 at 13:35

Hitmands

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14 Comments

kit Over a year ago

map or flatMap?

Hitmands Over a year ago

You can use both, but flatMap is definitely better.

kit Over a year ago

then change your answer

joshua1991 Over a year ago

how do i incorporate having to do a for loop through apiService.findVH into this?

Hitmands Over a year ago

you don't have to loop anything, Observable is an Iterable Object. Just look at my example.

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