Transaction behaviour of dispatch()

[arusakov]

Hi!
Each store.dispatch(/* some action */) will invoke all listeners callbacks. This can lead to a lot of unnecessary calls.
I propose to add some transaction-like behaviour.

store.begin();
store.dispatch({type: 1});
store.dispatch({type: 2});
// ...
store.dispatch({type: 100});
store.commit(); // and invoke listeners callbacks one time at the end

It seems to me, that the idea of transaction would be very useful in redux. But this PR has big changes in API and need some work.
Maybe another API seem more successful. Something like this easier to implement:

function dispatch(action, notNotify=false) {
// ...
}

// in app
store.dispatch({type: 1}, true);
store.dispatch({type: 2}, true);
// ...
store.dispatch({type: 100}); // and invoke listeners callbacks one time at the end

[danielkcz]

Transaction seems like bad term for this because there is no rollback which is expected from such approach. Instead I would probably call it batch. And I am not sure if batching is really necessary. I needed something like this some time ago, but I managed to implement it with simple store enhancer.

[arusakov]

@FredyC batch is a good term for this. Thanks. Maybe redux-batched-subscribe is what I need.
But maybe batching inside redux will be more holistic solution. I don't know.

[gaearon]

We don't want to expand Store API surface.
See #303 (comment) for rationale.
Indeed, redux-batched-subscribe solves this in userland.