Add topic filter

app/src/reducers/Tree.ts

@@ -0,0 +1,49 @@
+import * as q from '../../../backend/src/Model'
+import { Action } from 'redux'
+import { createReducer } from './lib'
+
+export interface TreeState {
+  tree?: q.Tree
+  selectedTopic?: q.TreeNode
+  filter?: string
+}
+
+export type Action = ShowTree | SelectTopic
+
+export enum ActionTypes {
+  TREE_SHOW_TREE = 'TREE_SHOW_TREE',
+  TREE_SELECT_TOPIC = 'TREE_SELECT_TOPIC',
+}
+
+export interface ShowTree {
+  type: ActionTypes.TREE_SHOW_TREE
+  tree?: q.Tree
+  filter?: string
+}
+
+export interface SelectTopic {
+  type: ActionTypes.TREE_SELECT_TOPIC
+  selectedTopic?: q.TreeNode
+}
+
+const initialState: TreeState = { }
+
+export const treeReducer = createReducer(initialState, {
+  TREE_SHOW_TREE: showTree,
+  TREE_SELECT_TOPIC: selectTopic,
+})
+
+function showTree(state: TreeState, action: ShowTree) {
+  return {
+    ...state,
+    tree: action.tree,
+    filter: action.filter,
+  }
+}
+
+function selectTopic(state: TreeState, action: SelectTopic) {
+  return {
+    ...state,
+    selectedTopic: action.selectedTopic,
+  }
+}