Selector proposal

src/processModules.js

@@ -5,38 +5,38 @@ export default function processModules(modules) {
     .filter(module => (
       typeof module.reducer == 'function' || typeof module.reducer == 'object'
     ))
-    .map(module => (
-      typeof module.reducer == 'function' ? module.reducer : handleActions(module.reducer)
-    ))
+    .map(module => {
+      const reducer = typeof module.reducer == 'function' ? module.reducer : handleActions(module.reducer)
+      const path = module.selector ? module.selector.split('.') : []
+
+      return !path.length ? reducer : (state, action) => {
+        const selection = path.reduce((state, key) => state && state[key] || {}, state)
+        const result = reducer(selection, action)
+        const changes = path.concat(null).reverse().reduce(
+          (state, key) => key ? ({ [key]: state }) : result, {}
+        )
+
+        return Object.assign({}, state, changes)
+      }
+    })
 
   const middlewares = modules
-    .filter(module => (
-      typeof module.middleware == 'function' || typeof module.middleware == 'object'
-    ))
-    .map(module => (
-      typeof module.middleware == 'function' ? module.middleware : handleMiddlewares(module.middleware)
-    ))
+    .map(module => module.middleware)
+    .filter(middleware => typeof middleware == 'function' || typeof middleware == 'object')
+    .map(middleware => typeof middleware == 'function' ? middleware : handleMiddlewares(middleware))
 
   const enhancers = modules
-    .filter(module => (
-      typeof module.enhancer == 'function'
-    ))
     .map(module => module.enhancer)
+    .filter(enhancer => typeof enhancer == 'function')
 
   return {
     reducers,
     middlewares,
-    enhancers
+    enhancers,
   }
 }
 
-export function handleMiddlewares(listeners) {
-  return store => next => action => {
-    // Execute action listeners, if any was set for the current action.
-    if (listeners[action.type]) {
-      return listeners[action.type](store)(next)(action)
-    }
-
-    return next(action)
-  }
-}
+export const handleMiddlewares = (listeners) => store => next => action => (
+  // Execute action listeners, if any was set for the current action.
+  listeners[action.type] ? listeners[action.type](store)(next)(action) : next(action)
+)