Reactjs 如何循环epic呼叫

我有以下建议：

import {
  map,
  catchError,
  switchMap,
  takeUntil,
} from 'rxjs/operators';
import {
  FETCH_JOKES,
  jokesReceived,
  FETCH_JOKES_CANCELLED,
  jokesFetchFailed,
} from '../actions/jokes-action';
import { ofType } from 'redux-observable';
import { of, concat } from 'rxjs';
import { ajax } from 'rxjs/ajax';

const getJokes = () =>
  ajax.getJSON('http://api.icndb.com/jokes/random?escape=javascript');

const fetchJokesEpic = action$ => {
  return action$.pipe(
    ofType(FETCH_JOKES),
    switchMap(() =>
      getJokes().pipe(
        map(response => jokesReceived(response)),
        catchError((err, act) => of(jokesFetchFailed(err))),
        takeUntil(action$.pipe(ofType(FETCH_JOKES_CANCELLED)))
      )
    ),
  );
};

export default fetchJokesEpic;

每当调度

FETCH\u jones

时，此epic将启动

ajax

调用，并在成功调度

joksreceived

操作或失败时

joksfetchfailed

我想循环它，除非取消，否则在上一次调用完成（成功或失败）后将再次调用端点

我想我可以使用另一个epic taht来对收到的

笑话

和

取回笑话

错误动作做出反应，然后发送

取回笑话

动作，该动作应该再次启动cricle

import { ofType } from 'redux-observable';
import {
  delay,
  map,
} from 'rxjs/operators';
import {
  JOKES_RECEIVED,
  FETCH_JOKES_CANCELLED,
  FETCH_JOKES_ERROR,
  fetchJokes,
} from '../actions/jokes-action';

const pollJokes = (action$, state$) => {
  return action$.pipe(
    ofType(JOKES_RECEIVED, FETCH_JOKES_ERROR, FETCH_JOKES_CANCELLED),
    delay(2000),
    map(action => {
      console.log('pollJokes.map', action);
      if(action.type === FETCH_JOKES_CANCELLED)
      { 
        console.log("Cancelled")
        return { type: 'POLL_STOPPED' };
      }
      else {
        // loop
        return fetchJokes();
      }
    })
  );
};
export default pollJokes;

但是，当我调度

获取\u取消
操作时，这不起作用。操作堆栈如下所示：

@INIT
FETCH_JOKES
JOKES_RECEIVED
FETCH_JOKES
JOKES_RECEIVED
...
FETCH_JOKES_CANCELLED
FETCH_JOKES
JOKES_RECEIVED
POLL_STOPPED
FETCH_JOKES
JOKES_RECEIVED
...

我曾尝试将
takeUntil
添加到
polljones
epic中，但结果同样糟糕

const pollJokes = (action$, state$) => {
  return action$.pipe(
    ofType(JOKES_RECEIVED, FETCH_JOKES_ERROR, FETCH_JOKES_CANCELLED),
    delay(2000),
    map(action => {
      console.log('pollJokes.map', action);
      if(action.type === FETCH_JOKES_CANCELLED)
      { 
        console.log("Cancelled")
        return { type: 'POLL_STOPPED' };
      }
      else {
        // loop
        return fetchJokes();
      }
    }),


    takeUntil(action$.pipe(ofType(FETCH_JOKES_CANCELLED)))


  );
};

使用此方法，
polljones
epic在第一次调度
FETCH\u jones\u CANCELLED
时停止工作。现在我知道史诗是在
takeUntil
上完成的

我该怎么做才能让这个“循环”工作？我想我可以实现一个中间件，当收到
笑话
发送时，它将实际调用
获取笑话
，但我正在搜索一个全rxjs解决方案，
您需要使用
重复
，以便在epic被
取消后重新启动epic

const pollJokes = (action$, state$) => {
  return action$.pipe(
    ofType(JOKES_RECEIVED, FETCH_JOKES_ERROR, FETCH_JOKES_CANCELLED),
    delay(2000),
    map(action => {
      console.log('pollJokes.map', action);
      if(action.type === FETCH_JOKES_CANCELLED)
      { 
        console.log("Cancelled")
        return { type: 'POLL_STOPPED' };
      }
      else {
        // loop
        return fetchJokes();
      }
    }),


    takeUntil(action$.pipe(ofType(FETCH_JOKES_CANCELLED))),
    repeat()

  );
};

的确，这很有帮助，但我相信我已经尝试过：），这个问题还有其他解决方案吗？