Rxjs：輪詢數據直到滿足謂詞

Question

import {Observable} from '@reactivex/rxjs'

// This is a fake API polling, this data is in reality coming from
// the server
const fakePoll$ = Observable.from([
  {
    status: 'initialized',
    data: {...},
  },
  {
    status: 'progress',
    data: {...},
  },
  {
    status: 'progress',
    data: {...},
  },
  {
    status: 'progress',
    data: {...},
  },
  {
    status: 'completed',
    data: {...},
  },
  ...
  {
    status: 'completed',
    data: {...},
  },
])

fakePoll$
  .takeWhile(x => x.status != 'completed')
  .subscribe(x => console.log(x))

此代碼段返回所有進度和初始化狀態：

initialized
progress
progress
progress

但我需要完成第一個也像 takeWhile 但包容。

Answer 1

如果您只需要這樣，您可以考慮將其添加回此處：

Rx.Observable.concat(fakePoll$
  .takeWhile(x => x != 'completed'), Rx.Observable.from('completed'))
  .subscribe(x => console.log(x))

Answer 2

我相信您在使用 api 時必須使用重復，假設它是一個承諾返回調用。 我這樣做了
服務器輪詢// 代碼放在這里

angular.module('rxApp', ['rx'])
  .controller('AppCtrl', function($scope, $http, rx) {
    function getRandom(){
       return Math.floor(Math.random() * (10 - 1)) + 1;
    }

    function getResults(){
       console.log("returning promise");
       return $http({
          url: "https://en.wikipedia.org/w/api.php?&callback=JSON_CALLBACK",
          method: "jsonp",
          params: {
            action: "opensearch",
            search: 'eclipse',
            format: "json"
          }
        });
    }
    var toBeRepeated =  rx.Observable
    .fromPromise(getResults).repeat()
    .map(response => { console.log(response); return response.data[1]; })
    .map(results => {
        var rs = results[getRandom()];
        console.log(rs);
        return rs;
    });             

    var source = toBeRepeated.takeWhile(rs => rs.indexOf('play') === -1);
        source.subscribe(function(item){
        console.log("item:"+ item);
    },err => { console.log(err); },completed => {console.log("completed :" + completed);} );
});

希望這可以幫助。