title: Reducing an entire subtree with redux combineReducers
body: <p>I have a reducer tree that looks like this:</p>
  
  <pre><code>module.exports = combineReducers({
      routing: routeReducer,
      app: combineReducers({
          setup: combineReducers({
              sets,
              boosters
          }),
          servers: combineReducers({
              servers
          })
      })
  });
  </code></pre>
  
  <p>Now the <code>setup</code> key holds a form that needs to be reset once we've submitted it. However I have no way to access the entire <code>setup</code> tree because using combineReducers means the reducers only manipulate the data at the leaf nodes of the tree (<code>sets</code> and <code>boosters</code> in this case).</p>
  
  <p>My first impulse is to make a function that reduces the entire setup tree like this:</p>
  
  <pre><code>function setup(state, action){
      //If there's an action that affects this whole tree, handle it
      switch(action.type){
          case "FORM_SUBMIT": //DO STUFF
          break;
      }
  
      //Otherwise just let the reducers care about their own data
      return combineReducers({
                  sets,
                  boosters
      })(state);
  }
  </code></pre>
  
  <p>But that doesn't work, and also messes up the nice tree structure of my first code example.</p>
  
  <p>Is there a better solution for this with redux?</p>