Reset store after disconnect

app/src/reducers/Tree.ts

@@ -1,22 +1,26 @@
 import * as q from '../../../backend/src/Model'
 import { Action } from 'redux'
 import { createReducer } from './lib'
+import { Record } from 'immutable'
 import { TopicViewModel } from '../model/TopicViewModel'
 
-export interface TreeState {
+interface TreeStateModel {
   tree?: q.Tree<TopicViewModel>
   selectedTopic?: q.TreeNode<TopicViewModel>
   filter?: string
   paused: boolean
 }
 
-export type Action = ShowTree | SelectTopic
+export type TreeState = Record<TreeStateModel>
+
+export type Action = ShowTree | SelectTopic | ResetStore
 
 export enum ActionTypes {
   TREE_SHOW_TREE = 'TREE_SHOW_TREE',
   TREE_SELECT_TOPIC = 'TREE_SELECT_TOPIC',
   TREE_RESUME_UPDATES = 'TREE_RESUME_UPDATES',
   TREE_PAUSE_UPDATES = 'TREE_PAUSE_UPDATES',
+  TREE_RESET_STORE = 'TREE_RESET_STORE',
 }
 
 export interface ShowTree {
@@ -34,35 +38,42 @@ export interface SetPause {
   type: ActionTypes.TREE_PAUSE_UPDATES | ActionTypes.TREE_RESUME_UPDATES
 }
 
-const initialState: TreeState = {
+const initialStateFactory = Record<TreeStateModel>({
   paused: false,
+  tree: undefined,
+  selectedTopic: undefined,
+  filter: undefined,
+})
+
+const setPaused = (pause: boolean) => (state: TreeState, action: ShowTree): TreeState => {
+  return state.set('paused', pause)
 }
 
-const setPaused = (pause: boolean) => (state: TreeState, action: ShowTree) => {
-  return {
-    ...state,
-    paused: pause,
-  }
-}
-
-export const treeReducer = createReducer(initialState, {
+const actions: {[s: string]: (state: TreeState, action: Action) => TreeState} = {
   TREE_SHOW_TREE: showTree,
   TREE_SELECT_TOPIC: selectTopic,
   TREE_PAUSE_UPDATES: setPaused(true),
   TREE_RESUME_UPDATES: setPaused(false),
-})
+  TREE_RESET_STORE: resetStore,
+}
 
-function showTree(state: TreeState, action: ShowTree) {
-  return {
-    ...state,
+export const treeReducer = createReducer(initialStateFactory(), actions)
+
+function showTree(state: TreeState, action: ShowTree): TreeState {
+  return state.merge({
     tree: action.tree,
     filter: action.filter,
-  }
+  })
 }
 
-function selectTopic(state: TreeState, action: SelectTopic) {
-  return {
-    ...state,
-    selectedTopic: action.selectedTopic,
-  }
+function selectTopic(state: TreeState, action: SelectTopic): TreeState {
+  return state.set('selectedTopic', action.selectedTopic)
+}
+
+export interface ResetStore {
+  type: ActionTypes.TREE_RESET_STORE
+}
+
+function resetStore(state: TreeState, action: ResetStore): TreeState {
+  return initialStateFactory()
 }