example of reducer handlers in an object

reducer.js

import {
  BLUEPRINTS_FILTER_UPDATE_VALUES,
  COMPONENTS_FILTER_UPDATE_VALUES, COMPONENTS_FILTER_ADD_VALUE
} from '../actions/filter';

// const filter = (state = [], action) => {
//   switch (action.type) {
//     case COMPONENTS_FILTER_ADD_VALUE:
//       // ...
//       return Object.assign({}, state,
//         { components: Object.assign({}, state.components,
//           { filterValue: updated })
//         });
//     case SOME_OTHER_ACTION:
//       // ...
//       return something;

//     default:
//       return state;
//   }
// };

const handlers = {
  [COMPONENTS_FILTER_ADD_VALUE]: (state, action) => {
    // ...
    return Object.assign({}, state,
      { components: Object.assign({}, state.components,
        { filterValue: updated })
      });
  },

  [SOME_OTHER_ACTION]: (state, action) => {
    // ...
    // return something;
  }
};


const filter = (state = [], action) => {
  const handler = handlers[action.type];
  if (handler) {
    return handler(state, action);
  }
  return state;
};


export default filter;