Rxjs:轮询数据直到满足谓词

Rxjs: Poll data until predicate is met

本文关键字：满足 谓词 数据 Rxjs      更新时间：2023-09-26
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))

这个代码片段返回所有的进度和初始化状态:

initialized
progress
progress
progress

但我需要得到第一个完成也像一个takeWhile但包括。

如果需要的话，可以考虑像这样重新添加:

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

我相信你必须使用重复时使用api假设它是一个承诺返回调用。我在
中做了这个服务器轮询//代码在这里

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);} );
});

相关文章：