Pass child monitor states

Related to #2

Author: zalmoxisus

src/FilterMonitor.js

@@ -1,7 +1,8 @@
 import { cloneElement, Component, PropTypes } from 'react';
+import reducer from './reducers';
 
 export default class FilterMonitor extends Component {
-  static update = () => ({});
+  static update = reducer;
 
   static propTypes = {
     children: PropTypes.element,
@@ -10,23 +11,28 @@ export default class FilterMonitor extends Component {
   };
 
   render() {
-    const { whitelist, blacklist, children, ...childProps } = this.props;
+    const { whitelist, blacklist, monitorState, children, ...rest } = this.props;
 
     if (whitelist || blacklist) {
-      let { stagedActionIds, actionsById } = childProps;
+      let { stagedActionIds, actionsById } = rest;
       stagedActionIds = stagedActionIds.filter(id => {
         const action = actionsById[id].action;
         return (
           whitelist && whitelist.indexOf(action.type) !== -1 ||
           blacklist && blacklist.indexOf(action.type) === -1
         );
       });
-      childProps = {
-        ...childProps,
+
+      rest = {
+        ...rest,
         stagedActionIds: stagedActionIds
       };
     }
 
+    const childProps = {
+      ...rest,
+      monitorState: monitorState.childMonitorState || {}
+    };
     return cloneElement(children, childProps);
   }
 }

src/reducers.js

@@ -0,0 +1,10 @@
+function childMonitorState(props, state, action) {
+  const child = props.children;
+  return child.type.update(child.props, state, action);
+}
+
+export default function reducer(props, state = {}, action) {
+  return {
+    childMonitorState: childMonitorState(props, state.childMonitorState, action)
+  };
+}