/*
  From egghead.io lesson on using forkJoin
  
  Gets array of ids from hnUrl and uses forkJoin to flatten
  the results from subsequest ajax requests into an
  array of result objects.
*/

'use strict';

var _Rx = Rx;
var Observable = _Rx.Observable;

var hnUrl = 'https://hacker-news.firebaseio.com/v0/topstories.json';
var itemUrl = function itemUrl(id) {
  return 'https://hacker-news.firebaseio.com/v0/item/' + id + '.json';
};

Observable.ajax(hnUrl).map(function (data) {
  return data.response.slice(0, 3);
}).switchMap(function (ids) {
  return Observable.forkJoin(ids.map(function (id) {
    var url = itemUrl(id);
    return Observable.ajax(url).map(function (e) {
      return e.response;
    });
  }));
}).subscribe(function (result) {
  return console.log(result);
});