Question

我尝试在节点6.2.1上运行下一个代码。它会记录 1,2，，然后卡住。我无法理解为什么它不继续执行到线路收益（＆＃39; TEST＆＃39;）...似乎anotherSaga完成并记录2但控制权没有返回到rootSaga。有人可以帮帮我吗？

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：但没有runSaga的代码按预期方式运行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

看起来这是由于subscribe函数没有返回正确的值。在它之上返回setInterval的结果，这将是间隔的ID。相反，它应该返回一个函数，redux-saga可以根据docs取消订阅事件。所以你的subscribe函数看起来应该更像这样：

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

用它运行它，我能够看到它循环打印

1
2
3
4
{ type: 'TEST' }

这是多么奇怪，这会导致你的传奇被卡住，但我假设没有从unsubscribe收到subscribe函数导致在redux内部搞砸了-saga。

Redux-saga一直停留在收益率调用上

1 个答案: