title: Calling a method after state change
body: <p>I am trying Redux in a project.
  I have a list of countries, all of which have a price, and I want to select the countries with prices between <code>minPrice</code> and <code>maxPrice</code> values. I am doing that in this method:</p>
  
  <pre><code>  filterPrice: function(minPrice, maxPrice) {
      var newCountries = [];
      _.forEach(this.props.countries, function(country) {
          var price = country["price"];
          if(minPrice &lt;= price &amp;&amp; price &lt;= maxPrice) {
              newCountries.push(country);
          }
      });
      this.setState({countries: newCountries});
    }
  </code></pre>
  
  <p>Now, I would like this method to be called somehow by the Redux architecture.</p>
  
  <p>I have this reducer:</p>
  
  <pre><code>const initialState = {
    minPrice: 0,
    maxPrice: Constants.PRICE_RANGE
  };
  
  
  export default function PriceReducer(state = initialState, action) {
    switch (action.type) {
  
      case types.UPDATE_MAX:
        return {
          maxPrice: action.maxPrice
        }
      case types.UPDATE_MIN:
        return {
          minPrice: action.minPrice
        }
  
      default:
        return state;
    }
  }
  </code></pre>
  
  <p>And these actions:</p>
  
  <pre><code>export const updateMax = (maxPrice) =&gt; {
    return {
      type: types.UPDATE_MAX,
      maxPrice: maxPrice
    };
  }
  
  export const updateMin = (minPrice) =&gt; {
    return {
      type: types.UPDATE_MIN,
      minPrice: minPrice
    };
  }
  </code></pre>
  
  <p>I am creating a store like this:</p>
  
  <pre><code>const store = createStore(PriceReducer);
  </code></pre>
  
  <p>And I am calling it like this:</p>
  
  <pre><code>store.dispatch({type: types.UPDATE_MIN, minPrice: 10});
  </code></pre>
  
  <p>So how can I call <code>filterPrice</code>?
  Or if I can't call it, how do I change the state?</p>