getState in mapDispatchToProps

Since mapDispatchToProps can expose the dispatch method, it means it has access to the store. I was wondering why it didn’t also expose, at least, the getState method?

Just like redux-thunk, you might need to access the current state to decide which action to actually dispatch regarding client side cache.

I’m fine with doing a PR but wanted to check if it would be valid. Also, if accepted, I would rather have [mapDispatchToProps(dispatch, [getState], [ownProps]): dispatchProps] signature, but it would be a breaking change compared to [mapDispatchToProps(dispatch, [ownProps], [getState]): dispatchProps]

[gaearon]

Have you looked at Redux Thunk?

It lets you write stuff like

function getSuggestions(query) {
  return (dispatch, getState) => {
    if (getState().suggestions[query]) {
      return;
    }

    return API.getSuggestions().then(
      response => dispatch({ type: 'SUGGESTIONS_RESPONSE', response }),
      error => dispatch({ type: 'SUGGESTIONS_ERROR', error })
    )
  };
}

// in component

class Stuff extends Component { /* ... */ }

export default connect(
  mapStateToProps,
  { getSuggestions }
)(Stuff)

[jimbolla]

mapDispatchToProps will never be dependent on state, because doing so would mean it would get invoked every time the store state changes, creating new functions each time, causing the component to rerender every time. mapDispatchToProps already does a lot of logic to minimize this when props change, which is bad enough. I personally never even use the version that accepts props, to avoid unnecessary rerenders. You’re a million bajillion times better off exposing a few props you don’t really need than generating new functions and renders on every state change.