Function takeLatest

takeLatest<P extends ActionPattern>(
pattern: P,
worker: (action: ActionMatchingPattern<P>) => any,
): ForkEffect<never>
Spawns a saga on each action dispatched to the Store that matches pattern. And automatically cancels any previous saga task started previously if it's still running.

Each time an action is dispatched to the store. And if this action matches pattern, takeLatest starts a new saga task in the background. If a saga task was started previously (on the last action dispatched before the actual action), and if this task is still running, the task will be cancelled.

Example
In the following example, we create a basic task fetchUser. We use takeLatest to start a new fetchUser task on each dispatched USER_REQUESTED action. Since takeLatest cancels any pending task started previously, we ensure that if a user triggers multiple consecutive USER_REQUESTED actions rapidly, we'll only conclude with the latest action

import { takeLatest } from redux-saga/effects

function* fetchUser(action) { ... }

function* watchLastFetchUser() { yield takeLatest('USER_REQUESTED', fetchUser) }

Notes
takeLatest is a high-level API built using take and fork. Here is how the helper could be implemented using the low-level Effects

const takeLatest = (patternOrChannel, saga, ...args) => fork(function*() { let lastTask while (true) { const action = yield take(patternOrChannel) if (lastTask) { yield cancel(lastTask) // cancel is no-op if the task has already terminated } lastTask = yield fork(saga, ...args.concat(action)) } })
Type Parameters
- P extends ActionPattern
Parameters
- pattern: P
  for more information see docs for take(pattern)
- worker: (action: ActionMatchingPattern<P>) => any
Returns ForkEffect<never>
- Defined in node_modules/@redux-saga/core/types/ts4.2/effects.d.ts:256
takeLatest<P extends ActionPattern, Fn extends (...args: any[]) => any>(
    pattern: P,
    worker: Fn,
    ...args: HelperWorkerParameters<ActionMatchingPattern<P>, Fn>,
): ForkEffect<never>
Spawns a saga on each action dispatched to the Store that matches pattern. And automatically cancels any previous saga task started previously if it's still running.

Each time an action is dispatched to the store. And if this action matches pattern, takeLatest starts a new saga task in the background. If a saga task was started previously (on the last action dispatched before the actual action), and if this task is still running, the task will be cancelled.

Example
In the following example, we create a basic task fetchUser. We use takeLatest to start a new fetchUser task on each dispatched USER_REQUESTED action. Since takeLatest cancels any pending task started previously, we ensure that if a user triggers multiple consecutive USER_REQUESTED actions rapidly, we'll only conclude with the latest action

import { takeLatest } from redux-saga/effects

function* fetchUser(action) { ... }

function* watchLastFetchUser() { yield takeLatest('USER_REQUESTED', fetchUser) }

Notes
takeLatest is a high-level API built using take and fork. Here is how the helper could be implemented using the low-level Effects

const takeLatest = (patternOrChannel, saga, ...args) => fork(function*() { let lastTask while (true) { const action = yield take(patternOrChannel) if (lastTask) { yield cancel(lastTask) // cancel is no-op if the task has already terminated } lastTask = yield fork(saga, ...args.concat(action)) } })
Type Parameters
- P extends ActionPattern
- Fn extends (...args: any[]) => any
Parameters
- pattern: P
  for more information see docs for take(pattern)
- worker: Fn
- ...args: HelperWorkerParameters<ActionMatchingPattern<P>, Fn>
  arguments to be passed to the started task. takeLatest will add the incoming action to the argument list (i.e. the action will be the last argument provided to saga)
Returns ForkEffect<never>
- Defined in node_modules/@redux-saga/core/types/ts4.2/effects.d.ts:260
takeLatest<A extends Action>(
pattern: ActionPattern<A>,
worker: (action: A) => any,
): ForkEffect<never>
Spawns a saga on each action dispatched to the Store that matches pattern. And automatically cancels any previous saga task started previously if it's still running.

Each time an action is dispatched to the store. And if this action matches pattern, takeLatest starts a new saga task in the background. If a saga task was started previously (on the last action dispatched before the actual action), and if this task is still running, the task will be cancelled.

Example
In the following example, we create a basic task fetchUser. We use takeLatest to start a new fetchUser task on each dispatched USER_REQUESTED action. Since takeLatest cancels any pending task started previously, we ensure that if a user triggers multiple consecutive USER_REQUESTED actions rapidly, we'll only conclude with the latest action

import { takeLatest } from redux-saga/effects

function* fetchUser(action) { ... }

function* watchLastFetchUser() { yield takeLatest('USER_REQUESTED', fetchUser) }

Notes
takeLatest is a high-level API built using take and fork. Here is how the helper could be implemented using the low-level Effects

const takeLatest = (patternOrChannel, saga, ...args) => fork(function*() { let lastTask while (true) { const action = yield take(patternOrChannel) if (lastTask) { yield cancel(lastTask) // cancel is no-op if the task has already terminated } lastTask = yield fork(saga, ...args.concat(action)) } })
Type Parameters
- A extends Action
Parameters
- pattern: ActionPattern<A>
  for more information see docs for take(pattern)
- worker: (action: A) => any
Returns ForkEffect<never>
- Defined in node_modules/@redux-saga/core/types/ts4.2/effects.d.ts:265
takeLatest<A extends Action, Fn extends (...args: any[]) => any>(
    pattern: ActionPattern<A>,
    worker: Fn,
    ...args: HelperWorkerParameters<A, Fn>,
): ForkEffect<never>
Spawns a saga on each action dispatched to the Store that matches pattern. And automatically cancels any previous saga task started previously if it's still running.

Each time an action is dispatched to the store. And if this action matches pattern, takeLatest starts a new saga task in the background. If a saga task was started previously (on the last action dispatched before the actual action), and if this task is still running, the task will be cancelled.

Example
In the following example, we create a basic task fetchUser. We use takeLatest to start a new fetchUser task on each dispatched USER_REQUESTED action. Since takeLatest cancels any pending task started previously, we ensure that if a user triggers multiple consecutive USER_REQUESTED actions rapidly, we'll only conclude with the latest action

import { takeLatest } from redux-saga/effects

function* fetchUser(action) { ... }

function* watchLastFetchUser() { yield takeLatest('USER_REQUESTED', fetchUser) }

Notes
takeLatest is a high-level API built using take and fork. Here is how the helper could be implemented using the low-level Effects

const takeLatest = (patternOrChannel, saga, ...args) => fork(function*() { let lastTask while (true) { const action = yield take(patternOrChannel) if (lastTask) { yield cancel(lastTask) // cancel is no-op if the task has already terminated } lastTask = yield fork(saga, ...args.concat(action)) } })
Type Parameters
- A extends Action
- Fn extends (...args: any[]) => any
Parameters
- pattern: ActionPattern<A>
  for more information see docs for take(pattern)
- worker: Fn
- ...args: HelperWorkerParameters<A, Fn>
  arguments to be passed to the started task. takeLatest will add the incoming action to the argument list (i.e. the action will be the last argument provided to saga)
Returns ForkEffect<never>
- Defined in node_modules/@redux-saga/core/types/ts4.2/effects.d.ts:266
takeLatest<T>(
channel: TakeableChannel<T>,
worker: (item: T) => any,
): ForkEffect<never>
You can also pass in a channel as argument and the behaviour is the same as takeLatest(pattern, saga, ...args).
Type Parameters
- T
Parameters
- channel: TakeableChannel<T>
- worker: (item: T) => any
Returns ForkEffect<never>
- Defined in node_modules/@redux-saga/core/types/ts4.2/effects.d.ts:276
takeLatest<T, Fn extends (...args: any[]) => any>(
    channel: TakeableChannel<T>,
    worker: Fn,
    ...args: HelperWorkerParameters<T, Fn>,
): ForkEffect<never>
Spawns a saga on each action dispatched to the Store that matches pattern. And automatically cancels any previous saga task started previously if it's still running.

Each time an action is dispatched to the store. And if this action matches pattern, takeLatest starts a new saga task in the background. If a saga task was started previously (on the last action dispatched before the actual action), and if this task is still running, the task will be cancelled.

Example
In the following example, we create a basic task fetchUser. We use takeLatest to start a new fetchUser task on each dispatched USER_REQUESTED action. Since takeLatest cancels any pending task started previously, we ensure that if a user triggers multiple consecutive USER_REQUESTED actions rapidly, we'll only conclude with the latest action

import { takeLatest } from redux-saga/effects

function* fetchUser(action) { ... }

function* watchLastFetchUser() { yield takeLatest('USER_REQUESTED', fetchUser) }

Notes
takeLatest is a high-level API built using take and fork. Here is how the helper could be implemented using the low-level Effects

const takeLatest = (patternOrChannel, saga, ...args) => fork(function*() { let lastTask while (true) { const action = yield take(patternOrChannel) if (lastTask) { yield cancel(lastTask) // cancel is no-op if the task has already terminated } lastTask = yield fork(saga, ...args.concat(action)) } })
Type Parameters
- T
- Fn extends (...args: any[]) => any
Parameters
- channel: TakeableChannel<T>
- worker: Fn
- ...args: HelperWorkerParameters<T, Fn>
  arguments to be passed to the started task. takeLatest will add the incoming action to the argument list (i.e. the action will be the last argument provided to saga)
Returns ForkEffect<never>
- Defined in node_modules/@redux-saga/core/types/ts4.2/effects.d.ts:277