How to make a global error handler in Redux and override it when needed?
<p>Imagine a situation of handling form submit which can return different errors: 400, 401, 500.
When 400 is returned, I want to show a message in top of the form (override the default behavior). 
For other (unhandled) error codes, the default (global) error handler should be invoked (which shows notification toast). Just don't want to duplicate this code for every single action</p>

<p>I dispatch async actions using redux-thunk middleware</p>

<pre><code>// Pseudo code
const action = (dispatch) =&gt; {

    const onSuccess = (result) =&gt; dispatch({type: 'OPERATION_SUCCESS', payload: result});
    const onError = (error) =&gt; dispatch({type: 'OPERATION_ERROR', error: true, payload: error});

    return promise.then(onSuccess, onError);

};
dispatch(action);
</code></pre>

<p>I can create a reducer which handles all <strong>{error: true}</strong> actions and show some popup-notification (probably without using redux state, directly invoking some toast.show() method)
But how to determine if this special error was already handled by some other reducer?</p>