Redux-saga: [Feature] Add takeFirst()

[mpyw]

takeEvery() and takeLatest() are already implemented, whereas takeFirst() is not.

fork(function* () {
  while (true) {
    const action = yield take(ACTION_TYPE)
    yield call(doSomethingAsync, action)
  }
})

I want to simplify it into:
(The signature concept is the same as takeEvery() or takeLatest())

takeFirst(ACTION_TYPE, function* (action) {
  yield call(doSomethingAsync, action)
})

I prefer builtin takeFirst() API to third-party ones.

[mpyw]

However, I also think it should be limited by user interface disabling rather than saga.

<button disabled={state.pending}>Submit</button>

[jpetitcolas]

We also need the takeFirst effect. Adding the logic on the component may be a good idea in some cases, yet it adds some complexity on components, which can be easily removed using this new effect.

[Andarist]

@jpetitcolas
Its easily implemented on the user-side with implementation provided by @mpyw . I would suggest creating ur own set of saga helpers anyway, so you can add it to those and import them just like effects - just from the other module.

There are no plans at the moment to expand on the built-in 'helpers', as the focus is on something else and the time is rly limited. That being said - I would love to create more robust helpers library in the future.