Operator concatMap()
did the job:
import { Observable } from 'rxjs/Observable';
import 'rxjs/add/operator/concatMap';
var urls = [
'https://httpbin.org/get?1',
'https://httpbin.org/get?2',
'https://httpbin.org/get?3',
'https://httpbin.org/get?4',
'https://httpbin.org/get?5',
];
Observable.from(this.urls)
.concatMap(url => http.get(url))
.subscribe(response => console.log(response.url))
;
This prints to console:
https://httpbin.org/get?1
https://httpbin.org/get?2
https://httpbin.org/get?3
https://httpbin.org/get?4
https://httpbin.org/get?5
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