feat: add segment decorator factory

modules/link-factory.js

@@ -4,9 +4,10 @@ import {element} from 'deku'
 // are not excluded
 export default linkFactory
 
-var listeners = {}
 
 function linkFactory(router) {
+    let listeners = {}
+
     let propTypes = {
         label:           {type: 'string', optional: false},
         button:          {type: 'boolean'},

modules/segment-decorator.js

@@ -0,0 +1,29 @@
+export default segmentDecoratorFactory
+
+function segmentDecoratorFactory(router) {
+    let listeners = {}
+
+    return function segmentDecorator(componentDef, routeName, listener) {
+        componentDef.afterMount = (component, el, setState) => {
+            function getListener(component) {
+                listeners[component.id] = (toState, fromState) => {
+                    listener(component, toState, fromState)
+                }
+                return isteners[component.id]
+            }
+
+            if (componentDef.afterMount) componentDef.afterMount(component, el, setState)
+
+            if (listener) router.addNodeListener(routeName, this.nodeListener)
+
+            router.registerComponent(routeName, component)
+        }
+
+        componentDef.beforeUnmount = (component, el) {
+            if (listener) router.removeNodeListener(routeName, listeners[component.id])
+            delete listeners[component.id]
+
+            router.deregisterComponent(routeName, this)
+        }
+    }
+}