Refactor task list example application

examples/task-list/src/reducer.ts

@@ -0,0 +1,45 @@
+import type { Task, TaskAction, TaskState } from './types';
+
+export const initialState: TaskState = {
+  tasks: [],
+  loading: false,
+  error: null,
+};
+
+export const taskReducer = (
+  state: TaskState,
+  action: TaskAction,
+): TaskState => {
+  switch (action.type) {
+    case 'set-tasks':
+      return { ...state, tasks: action.payload, loading: false };
+    case 'add-task':
+      return {
+        ...state,
+        tasks: [...state.tasks, action.payload],
+        loading: false,
+      };
+    case 'update-task':
+      const { id, ...payload } = action.payload;
+
+      return {
+        ...state,
+        tasks: state.tasks.map((task) =>
+          task.id === id ? { ...task, ...payload } : task,
+        ),
+        loading: false,
+      };
+    case 'remove-task':
+      return {
+        ...state,
+        tasks: state.tasks.filter((task) => task.id !== action.payload),
+        loading: false,
+      };
+    case 'set-loading':
+      return { ...state, loading: action.payload };
+    case 'set-error':
+      return { ...state, error: action.payload, loading: false };
+    default:
+      return state;
+  }
+};