我需要从 r 运行并行的任务中取消 redux saga 中的特定任务。使用下面的代码，所有并行任务都被取消

Question

function* imageUploadfunctionCall(payload) {
  for (let image of payload.payload) {
    const {response, error} = yield call(imageUploadRequest(image))
    if (response) {
      yield put({type: ON_UPLOAD_SUCCESS, payload: image})
    } else if (error) {
      console.log('error', error)
    }
  }
}

export function* watchImageUpload() {
  while (true) {
    let workerTask = yield takeEvery(
      ON_UPLOAD_PROGRESS,
      imageUploadfunctionCall
    )
    yield take(ON_CANCEL_BATCH_UPLOAD)
    yield cancel(workerTask)
  }
}

Answer 1

有多种方法可以做到这一点，例如，您可以使用具有 race 效果的中间传奇：

function* imageUploadfunctionCall(payload) {
  for (let image of payload.payload) {
    const {response, error} = yield call(imageUploadRequest(image))
    if (response) {
      yield put({type: ON_UPLOAD_SUCCESS, payload: image})
    } else if (error) {
      console.log('error', error)
    }
  }
}

function* imageUploadSaga(payload) {
  yield race([
    call(imageUploadfunctionCall, payload),
    take(a => a.type === ON_CANCEL_BATCH_UPLOAD && a.id === payload.id),
  ])
}

export function* watchImageUpload() {
  yield takeEvery(ON_UPLOAD_PROGRESS, imageUploadSaga)
}

上面的代码假定您为 ON_UPLOAD_PROGRESS 和 ON_CANCEL_BATCH_UPLOAD 操作都发送了一个 id 属性，这样您就可以确定要取消哪一个。

附带说明，在上传传奇中，您有：

yield call(imageUploadRequest(image))

应该是

yield call(imageUploadRequest, image)

（除非 imageUploadRequest 是函数工厂）。

对于更复杂的情况，您可以持有任务和 ID 的地图。

export function* watchImageUpload() {
  const taskMap = {}

  yield takeEvery(ON_CANCEL_BATCH_UPLOAD, function* (action) {
    if (!taskMap[action.payload]) return
    yield cancel(taskMap[action.payload])
    delete taskMap[action.payload]
  })

  while (true) {
    let payload = yield take(ON_UPLOAD_PROGRESS, imageUploadSaga)
    const workerTask = yield fork(imageUploadfunctionCall, payload)
    taskMap[payload.id] = workerTask
  }
}

同样，您在这两个操作中都需要一些 ID。

我需要从 r 运行并行的任务中取消 redux saga 中的特定任务。使用下面的代码，所有并行任务都被取消

I need to cancel a particular task in redux saga from the tasks which r running parallely. with the code below all of the parallel tasks are cancelled

reactjs

redux-saga

react-redux

我需要从 r 运行 并行的任务中取消 redux saga 中的特定任务。使用下面的代码，所有并行任务都被取消

I need to cancel a particular task in redux saga from the tasks which r running parallely. with the code below all of the parallel tasks are cancelled

reactjs

redux-saga

react-redux

我需要从 r 运行并行的任务中取消 redux saga 中的特定任务。使用下面的代码，所有并行任务都被取消