Have dispatch return the action it's provided after the current loop concludes

[erik-singleton]

The vanilla implementation of redux passes the provided action back as a convenience. The doc comment does mention that this isn't guaranteed behavior across middleware/store enhancers, but during our transition to redux-loop from redux-thunk, this characteristic of dispatch is important because it was pretty heavily relied on in the past.

Just looking at the code, it's unclear why we do not return the provided action. Especially if there are multiple actions in the cmdRun queue, we seem to discard the result of the Promises.

Applying this change has not broken our limited usage of redux-loop, and I'm curious if it may break in other places.

Thanks!

[bdwain]

Hi @sasucker. Thanks for the PR.

Can you explain a little more what you need the return value for? Especially because vanilla redux returns the value synchronously and this would return asynchronously, it seems like you'd have to change all of your code anyway.

[erik-singleton]

Hi @bdwain, thanks for getting back so quickly!

As mentioned, we previously (and currently) use redux-thunk for our async behavior. For better or for worse, some of our older components rely on the underlying Promise that is returned from an async thunk.

To illustrate:

function asyncAction() {
    return (dispatch) => {
        dispatch(fetching());
        return request().then(({data}) => {
            dispatch(complete(data));
            return data;
        });
    };
}

// although in actuality we'd use `bindActionCreators`, which also returns the `dispatch`
class SomeComponent {
    componentDidMount() {
        this.setState({loading: true});

        this.props.store.dispatch(asyncAction()).then((datas) => {
            this.setState({datas, loading: false});
        });
    }

    render() {
        return this.state.loading
            ? <h1>{this.state.datas}</h1>
            : <LoadingIndicator />;
    }
};

We've largely moved away from this pattern, but in the interest of transitioning it would definitely help us if redux-loop's dispatch also resolved with the provided action.

[bdwain]

Got it. Thanks for explaining. I don't see this being a problem since we currently always return undefined.

Sorry I couldn't get back sooner. I was pretty busy over the holidays.