Redux-saga被困在收益召唤上。

Question

我尝试在节点6.2.1上运行下一段代码。它记录1，2，，然后卡住。我无法解释为什么它不继续执行行产量采取(‘测试’).似乎anotherSaga完成并记录了2，但是控件没有返回到rootSaga。有人能帮我吗？

const {runSaga, delay} = require('redux-saga');
const {take, put, call} = require('redux-saga/effects');

function* anotherSaga() {
  yield call(delay, 1000);
  console.log(2);
}

function* rootSaga() {
  while(true) {
    console.log(1);
    yield call(anotherSaga);
    console.log(3);
    const action = yield take('TEST');
    console.log(4);
    yield put(action);
  }
}

runSaga(
  rootSaga(),
  {
    subscribe(callback) {
      return setInterval(() => (callback({type: 'TEST'})), 1000);
    },
    dispatch(action) {
      console.log(action);
    },
    getState() {}
  }
);

更新：但是没有runSaga的代码可以按预期日志记录工作1,2,3,4

const {createStore, applyMiddleware} = require('redux');
const createSagaMiddleware = require('redux-saga').default;
const {delay} = require('redux-saga');
const {take, put, call} = require('redux-saga/effects');

function* anotherSaga() {
  yield call(delay, 2000);
  console.log(2);
}

function* rootSaga() {
  while(true) {
    console.log(1);
    yield call(anotherSaga);
    console.log(3);
    const action = yield take('TEST');
    console.log(4);
    yield put(action);
    console.log('---')
  }
}

const rootReducer = (state, action) => {
  if (state === undefined) {
    return {};
  }

  return state;
}

const sagaMiddleware = createSagaMiddleware();
const store = createStore(rootReducer, {}, applyMiddleware(sagaMiddleware));
sagaMiddleware.run(rootSaga);

setInterval(() => (store.dispatch({type: 'TEST'})), 1000);

Answer 1

这看起来是由于subscribe函数没有返回正确的值。上面是返回setInterval的结果，这将是间隔的ID。相反，它应该返回redux可以用来取消订阅事件的函数，正如文档所示。因此，您的subscribe函数应该更像这样：

subscribe(callback) {
  const intervalId = setInterval(() => (callback({type: 'TEST'})), 1000);
  return () => { clearInterval(intervalId); };
},

通过这个运行它，我能够看到它通过打印循环。

1
2
3
4
{ type: 'TEST' }

奇怪的是，这是如何导致您的传奇成为卡住，但我假设，没有从unsubscribe函数从subscribe导致事情变得混乱内部在redux-传奇。