# 3.9 Общие паттерны параллелизма

In the basics section, we saw how to use the helper effects `takeEvery` and `takeLatest` in order to manage concurrency between Effects.

In this section we'll see how those helpers could be implemented using the low-level Effects.

## `takeEvery`

```javascript
import {fork, take} from "redux-saga/effects"

const takeEvery = (pattern, saga, ...args) => fork(function*() {
  while (true) {
    const action = yield take(pattern)
    yield fork(saga, ...args.concat(action))
  }
})
```

`takeEvery` allows multiple `saga` tasks to be forked concurrently.

## `takeLatest`

```javascript
import {cancel, fork, take} from "redux-saga/effects"

const takeLatest = (pattern, saga, ...args) => fork(function*() {
  let lastTask
  while (true) {
    const action = yield take(pattern)
    if (lastTask) {
      yield cancel(lastTask) // cancel is no-op if the task has already terminated
    }
    lastTask = yield fork(saga, ...args.concat(action))
  }
})
```

`takeLatest` doesn't allow multiple Saga tasks to be fired concurrently. As soon as it gets a new dispatched action, it cancels any previously-forked task (if still running).

`takeLatest` can be useful to handle AJAX requests where we want to only have the response to the latest request.