连接数据

到目前为止，我们已经创建了隔离的无状态组件——这对于 Storybook 来说很棒，但最终在我们为它们提供应用中的一些数据之前，它们并没有什么用处。

本教程不关注构建应用程序的细节，因此我们不会在此处深入探讨这些细节。但是，我们将花一点时间来了解将数据连接到已连接组件的常用模式。

已连接组件

我们目前编写的 `TaskList` 组件是“展示型”的，因为它不与其自身实现之外的任何内容对话。我们需要将其连接到数据提供程序以获取数据。

此示例使用 Redux Toolkit，这是用于开发使用 Redux 存储数据的应用程序的最有效工具集，来构建我们应用程序的简单数据模型。但是，此处使用的模式同样适用于其他数据管理库，如 Apollo 和 MobX。

使用以下命令将必要的依赖项添加到您的项目中

yarn add @reduxjs/toolkit react-redux

首先，我们将在 `src/lib` 目录中名为 store.ts 的文件中构建一个简单的 Redux store，它响应更改任务状态的操作（有意保持简单）

/* A simple redux store/actions/reducer implementation.
 * A true app would be more complex and separated into different files.
 */
import type { TaskData } from '../types';

import { configureStore, createSlice, PayloadAction } from '@reduxjs/toolkit';

interface TaskBoxState {
  tasks: TaskData[];
  status: 'idle' | 'loading' | 'failed';
  error: string | null;
}

/*
 * The initial state of our store when the app loads.
 * Usually, you would fetch this from a server. Let's not worry about that now
 */
const defaultTasks: TaskData[] = [
  { id: '1', title: 'Something', state: 'TASK_INBOX' },
  { id: '2', title: 'Something more', state: 'TASK_INBOX' },
  { id: '3', title: 'Something else', state: 'TASK_INBOX' },
  { id: '4', title: 'Something again', state: 'TASK_INBOX' },
];

const TaskBoxData: TaskBoxState = {
  tasks: defaultTasks,
  status: 'idle',
  error: null,
};

/*
 * The store is created here.
 * You can read more about Redux Toolkit's slices in the docs:
 * https://toolkit.redux.js.cn/api/createSlice
 */
const TasksSlice = createSlice({
  name: 'taskbox',
  initialState: TaskBoxData,
  reducers: {
    updateTaskState: (
      state,
      action: PayloadAction<{ id: string; newTaskState: TaskData['state'] }>
    ) => {
      const task = state.tasks.find((task) => task.id === action.payload.id);
      if (task) {
        task.state = action.payload.newTaskState;
      }
    },
  },
});

// The actions contained in the slice are exported for usage in our components
export const { updateTaskState } = TasksSlice.actions;

/*
 * Our app's store configuration goes here.
 * Read more about Redux's configureStore in the docs:
 * https://toolkit.redux.js.cn/api/configureStore
 */

const store = configureStore({
  reducer: {
    taskbox: TasksSlice.reducer,
  },
});

// Define RootState and AppDispatch types
export type RootState = ReturnType<typeof store.getState>;
export type AppDispatch = typeof store.dispatch;

export default store;

然后，我们将更新我们的 TaskList 组件以连接到 Redux store 并渲染我们感兴趣的任务

import Task from './Task';

import { useDispatch, useSelector } from 'react-redux';

import { updateTaskState, RootState, AppDispatch } from '../lib/store';

export default function TaskList() {
  // We're retrieving our state from the store
  const tasks = useSelector((state: RootState) => {
    const tasksInOrder = [
      ...state.taskbox.tasks.filter((t) => t.state === 'TASK_PINNED'),
      ...state.taskbox.tasks.filter((t) => t.state !== 'TASK_PINNED'),
    ];
    const filteredTasks = tasksInOrder.filter(
      (t) => t.state === "TASK_INBOX" || t.state === 'TASK_PINNED'
    );
    return filteredTasks;
  });
  const { status } = useSelector((state: RootState) => state.taskbox);
  const dispatch = useDispatch<AppDispatch>();
  const pinTask = (value: string) => {
    // We're dispatching the Pinned event back to our store
    dispatch(updateTaskState({ id: value, newTaskState: 'TASK_PINNED' }));
  };
  const archiveTask = (value: string) => {
    // We're dispatching the Archive event back to our store
    dispatch(updateTaskState({ id: value, newTaskState: 'TASK_ARCHIVED' }));
  };
  const LoadingRow = (
    <div className="loading-item">
      <span className="glow-checkbox" />
      <span className="glow-text">
        <span>Loading</span> <span>cool</span> <span>state</span>
      </span>
    </div>
  );
  if (status === "loading") {
    return (
      <div className="list-items" data-testid="loading" key="loading">
        {LoadingRow}
        {LoadingRow}
        {LoadingRow}
        {LoadingRow}
        {LoadingRow}
        {LoadingRow}
      </div>
    );
  }
  if (tasks.length === 0) {
    return (
      <div className="list-items" key="empty" data-testid="empty">
        <div className="wrapper-message">
          <span className="icon-check" />
          <p className="title-message">You have no tasks</p>
          <p className="subtitle-message">Sit back and relax</p>
        </div>
      </div>
    );
  }

  return (
    <div className="list-items" data-testid="success" key="success">
      {tasks.map((task) => (
        <Task
          key={task.id}
          task={task}
          onPinTask={pinTask}
          onArchiveTask={archiveTask}
        />
      ))}
    </div>
  );
}

现在我们有一些实际数据填充我们的组件，这些数据是从 Redux store 获取的，我们可以将其连接到 src/App.tsx 并在那里渲染该组件。但就目前而言，让我们暂缓这样做，继续我们的组件驱动之旅。

不用担心。我们将在下一章中处理它。

使用装饰器提供上下文

我们的 Storybook 故事已停止使用此更改，因为我们的 Tasklist 现在是一个已连接的组件，因为它依赖于 Redux store 来检索和更新我们的任务。

我们可以使用各种方法来解决此问题。不过，由于我们的应用程序非常简单，我们可以依赖一个装饰器，类似于我们在上一章中所做的，并在我们的 Storybook 故事中提供一个模拟 store

import type { Meta, StoryObj } from '@storybook/react';

import type { TaskData } from '../types';

import TaskList from './TaskList';

import * as TaskStories from './Task.stories';

import { Provider } from 'react-redux';

import { configureStore, createSlice } from '@reduxjs/toolkit';

// A super-simple mock of the state of the store
export const MockedState = {
  tasks: [
    { ...TaskStories.Default.args.task, id: '1', title: 'Task 1' },
    { ...TaskStories.Default.args.task, id: '2', title: 'Task 2' },
    { ...TaskStories.Default.args.task, id: '3', title: 'Task 3' },
    { ...TaskStories.Default.args.task, id: '4', title: 'Task 4' },
    { ...TaskStories.Default.args.task, id: '5', title: 'Task 5' },
    { ...TaskStories.Default.args.task, id: '6', title: 'Task 6' },
  ] as TaskData[],
  status: 'idle',
  error: null,
};

// A super-simple mock of a redux store
const Mockstore = ({
  taskboxState,
  children,
}: {
  taskboxState: typeof MockedState;
  children: React.ReactNode;
}) => (
  <Provider
    store={configureStore({
      reducer: {
        taskbox: createSlice({
          name: "taskbox",
          initialState: taskboxState,
          reducers: {
            updateTaskState: (state, action) => {
              const { id, newTaskState } = action.payload;
              const task = state.tasks.findIndex((task) => task.id === id);
              if (task >= 0) {
                state.tasks[task].state = newTaskState;
              }
            },
          },
        }).reducer,
      },
    })}
  >
    {children}
  </Provider>
);

const meta = {
  component: TaskList,
  title: 'TaskList',
  decorators: [(story) => <div style={{ margin: '3rem' }}>{story()}</div>],
  tags: ['autodocs'],
  excludeStories: /.*MockedState$/,
} satisfies Meta<typeof TaskList>;

export default meta;
type Story = StoryObj<typeof meta>;

export const Default: Story = {
  decorators: [
    (story) => <Mockstore taskboxState={MockedState}>{story()}</Mockstore>,
  ],
};

export const WithPinnedTasks: Story = {
  decorators: [
    (story) => {
      const pinnedtasks: TaskData[] = [
        ...MockedState.tasks.slice(0, 5),
        { id: '6', title: 'Task 6 (pinned)', state: 'TASK_PINNED' },
      ];

      return (
        <Mockstore
          taskboxState={{
            ...MockedState,
            tasks: pinnedtasks,
          }}
        >
          {story()}
        </Mockstore>
      );
    },
  ],
};

export const Loading: Story = {
  decorators: [
    (story) => (
      <Mockstore
        taskboxState={{
          ...MockedState,
          status: 'loading',
        }}
      >
        {story()}
      </Mockstore>
    ),
  ],
};

export const Empty: Story = {
  decorators: [
    (story) => (
      <Mockstore
        taskboxState={{
          ...MockedState,
          tasks: [],
        }}
      >
        {story()}
      </Mockstore>
    ),
  ],
};

成功！我们回到了起点，我们的 Storybook 现在可以工作了，并且我们能够看到如何将数据提供给已连接的组件。在下一章中，我们将运用我们在这里学到的知识并将其应用于屏幕。