如何在saga中使用redux动作关闭eventSource？

Question

我想通过按钮启动和停止eventSource。使用CONSTANTS.FETCHING_STOPPED操作的CONSTANTS.FETCHING_STARTED操作和停止按钮的开始按钮。

https://github.com/redux-saga/redux-saga/issues/940 - 不适合我。

我试过停止并启动一个功能，但它没有用。

这是我的传奇。

import {
  call,
  take,
  takeLatest,
  put,
  race,
  cancelled
} from "redux-saga/effects";
import { eventChannel, END } from "redux-saga";

import * as CONSTANTS from "../constants";

export function* innerSSE(eventSrc) {
  const eCh = eventChannel(emitter => {
    eventSrc.onmessage = msg => {
      emitter(msg);
    };

    eventSrc.onerror = () => {
      emitter(END);
    };

    return () => {
      eventSrc.close();
    };
  });

  try {
    yield takeLatest(eCh);
  } finally {
    if (yield cancelled()) eCh.close();
  }
}

function* start() {
  const eventSrc = new EventSource(CONSTANTS.STREAM_URL);
  const chan = yield call(innerSSE, eventSrc);

  while (true) {
    const msg = yield take(chan);

    yield put({
      type: CONSTANTS.FETCHING_IN_PROGRESS,
      payload: JSON.parse(msg.data)
    });
  }
}

function* stop(eventSrc) {
  // innerSSE.close()
}

export function* sseSaga() {
  while (true) {
    try {
      const started = yield take(CONSTANTS.FETCHING_STARTED);

      yield call(start, started);
    } catch (error) {
      console.log(error);
    }
  }
}

Answer 1

qazxsw poi => dispatch action => saga trigger

Answer 2

试试这个

componentWillUnMount()

Answer 3

function* main(){
  yield takeLatest(CONSTANTS.FETCHING_STARTED, function*(){
    // create event channel
    const chan = eventChannel(()=>{ /* ... */})

    yield takeEvery(chan, function*(){
        // process event
    })

    try{
        // waiting for FETCHING_STOPPED
        yield take(CONSTANTS.FETCHING_STOPPED)
    }finally{
        // or close by another FETCHING_STARTED
        chan.close()
    }
  })
}