redux example init

docs/examples/todos/src/reducers/todos.js

@@ -0,0 +1,23 @@
+const todos = (state = [], action) => {
+  switch (action.type) {
+    case 'ADD_TODO':
+      return [
+        ...state,
+        {
+          id: action.id,
+          text: action.text,
+          completed: false
+        }
+      ]
+    case 'TOGGLE_TODO':
+      return state.map(todo =>
+        (todo.id === action.id)
+          ? {...todo, completed: !todo.completed}
+          : todo
+      )
+    default:
+      return state
+  }
+}
+
+export default todos