Memahami React New Hooks

React 19 memperkenalkan beberapa cangkuk baharu yang hebat yang merevolusikan cara kami mengendalikan borang dan mengurus kemas kini optimistik dalam aplikasi kami. Dalam blog ini, kami akan meneroka useFormStatus, useActionState dan useOptimistic - tiga cangkuk yang menjadikan aplikasi React kami lebih responsif dan mesra pengguna.

useFormStatus: Pengendalian Borang Dipertingkat

Kait useFormStatus menyediakan maklumat masa nyata tentang penyerahan borang, menjadikannya lebih mudah untuk membuat borang yang responsif dan boleh diakses. Mari kita terokai cara cangkuk ini bertambah baik apabila keupayaan pengendalian borang React 18.

Contoh 1: Keadaan Pemuatan Borang Asas

function SubmitButton() {
  const { pending } = useFormStatus();

  return (
    <button disabled={pending}>
      {pending ? 'Submitting...' : 'Submit'}
    </button>
  );
}

function SignupForm() {
  return (
    <form action={async (formData) => {
      await submitSignupData(formData);
    }}>
      <input name="email" type="email" />
      <input name="password" type="password" />
      <SubmitButton />
    </form>
  );
}

Dalam React 18, anda perlu mengurus keadaan pemuatan secara manual menggunakan useState. Cangkuk useFormStatus baharu mengendalikan perkara ini secara automatik, mengurangkan kod boilerplate.

Contoh 2: Keadaan Berbilang Bentuk

function FormStatus() {
  const { pending, data, method } = useFormStatus();

  return (
    <div role="status">
      {pending && <span>Submitting via {method}...</span>}
      {!pending && data && <span>Last submission: {new Date().toLocaleString()}</span>}
    </div>
  );
}

function ContactForm() {
  return (
    <form action={async (formData) => {
      await submitContactForm(formData);
    }}>
      <textarea name="message" />
      <FormStatus />
      <SubmitButton />
    </form>
  );
}

Contoh 3: Status Pengesahan Borang

function ValidationStatus() {
  const { pending, validationErrors } = useFormStatus();

  return (
    <div role="alert">
      {validationErrors?.map((error, index) => (
        <p key={index} className="error">{error}</p>
      ))}
    </div>
  );
}

function RegistrationForm() {
  return (
    <form action={async (formData) => {
      const errors = validateRegistration(formData);
      if (errors.length) throw errors;
      await register(formData);
    }}>
      <input name="username" />
      <input name="email" type="email" />
      <ValidationStatus />
      <SubmitButton />
    </form>
  );
}

Contoh 4: Kemajuan Borang Berbilang Langkah

function FormProgress() {
  const { pending, step, totalSteps } = useFormStatus();

  return (
    <div className="progress-bar">
      <div 
        className="progress" 
       >



<h3>
  
  
  Example 5: File Upload Progress
</h3>



<pre class="brush:php;toolbar:false">function UploadProgress() {
  const { pending, progress } = useFormStatus();

  return (
    <div>
      {pending && progress && (
        <div className="upload-progress">
          <div 
            className="progress-bar" 
           >



<h2>
  
  
  useActionState: Managing Action Results
</h2>

<p>The useActionState hook provides a way to track the state of form actions and server mutations, making it easier to handle success and error states.</p>

<h3>
  
  
  Example 1: Basic Action State
</h3>



<pre class="brush:php;toolbar:false">function SubmissionStatus() {
  const state = useActionState();

  return (
    <div>
      {state.status === 'success' && <p>Submission successful!</p>}
      {state.status === 'error' && <p>Error: {state.error.message}</p>}
    </div>
  );
}

function CommentForm() {
  return (
    <form action={async (formData) => {
      await submitComment(formData);
    }}>
      <textarea name="comment" />
      <SubmissionStatus />
      <SubmitButton />
    </form>
  );
}

Contoh 2: Sejarah Tindakan

function ActionHistory() {
  const state = useActionState();

  return (
    <div>
      <h3>Recent Actions</h3>
      <ul>
        {state.history.map((action, index) => (
          <li key={index}>
            {action.type} - {action.timestamp}
            {action.status === 'error' && ` (Failed: ${action.error.message})`}
          </li>
        ))}
      </ul>
    </div>
  );
}

Contoh 3: Mekanisme Cuba Semula

function RetryableAction() {
  const state = useActionState();

  return (
    <div>
      {state.status === 'error' && (
        <button 
          onClick={() => state.retry()}
          disabled={state.retrying}
        >
          {state.retrying ? 'Retrying...' : 'Retry'}
        </button>
      )}
    </div>
  );
}

Contoh 4: Barisan Tindakan

function ActionQueue() {
  const state = useActionState();

  return (
    <div>
      <h3>Pending Actions</h3>
      {state.queue.map((action, index) => (
        <div key={index}>
          {action.type} - Queued at {action.queuedAt}
          <button onClick={() => action.cancel()}>Cancel</button>
        </div>
      ))}
    </div>
  );
}

Contoh 5: Statistik Tindakan

function ActionStats() {
  const state = useActionState();

  return (
    <div>
      <h3>Action Statistics</h3>
      <p>Success Rate: {state.stats.successRate}%</p>
      <p>Average Duration: {state.stats.avgDuration}ms</p>
      <p>Total Actions: {state.stats.total}</p>
    </div>
  );
}

useOptimistic: Kemas Kini UI Lancar

Kait useOptimistic mendayakan kemas kini UI serta-merta sambil menunggu respons pelayan, mewujudkan pengalaman pengguna yang lebih responsif.

Contoh 1: Senarai Todo Optimis

function TodoList() {
  const [todos, setTodos] = useState([]);
  const [optimisticTodos, addOptimisticTodo] = useOptimistic(
    todos,
    (state, newTodo) => [...state, newTodo]
  );

  async function addTodo(formData) {
    const newTodo = {
      id: Date.now(),
      text: formData.get('todo'),
      completed: false
    };

    addOptimisticTodo(newTodo);
    await saveTodo(newTodo);
  }

  return (
    <div>
      <form action={addTodo}>
        <input name="todo" />
        <button type="submit">Add Todo</button>
      </form>
      <ul>
        {optimisticTodos.map(todo => (
          <li key={todo.id}>{todo.text}</li>
        ))}
      </ul>
    </div>
  );
}

Contoh 2: Butang Suka Optimis

function LikeButton({ postId, initialLikes }) {
  const [likes, setLikes] = useState(initialLikes);
  const [optimisticLikes, addOptimisticLike] = useOptimistic(
    likes,
    (state) => state + 1
  );

  async function handleLike() {
    addOptimisticLike();
    await likePost(postId);
  }

  return (
    <button onClick={handleLike}>
      {optimisticLikes} Likes
    </button>
  );
}

Contoh 3: Benang Komen Optimis

function CommentThread({ postId }) {
  const [comments, setComments] = useState([]);
  const [optimisticComments, addOptimisticComment] = useOptimistic(
    comments,
    (state, newComment) => [...state, newComment]
  );

  async function submitComment(formData) {
    const comment = {
      id: Date.now(),
      text: formData.get('comment'),
      pending: true
    };

    addOptimisticComment(comment);
    await saveComment(postId, comment);
  }

  return (
    <div>
      <form action={submitComment}>
        <textarea name="comment" />
        <button type="submit">Comment</button>
      </form>
      {optimisticComments.map(comment => (
        <div key={comment.id}>



<h3>
  
  
  Example 4: Optimistic Shopping Cart
</h3>



<pre class="brush:php;toolbar:false">function ShoppingCart() {
  const [cart, setCart] = useState([]);
  const [optimisticCart, updateOptimisticCart] = useOptimistic(
    cart,
    (state, update) => {
      const { type, item } = update;
      switch (type) {
        case 'add':
          return [...state, item];
        case 'remove':
          return state.filter(i => i.id !== item.id);
        case 'update':
          return state.map(i => i.id === item.id ? item : i);
        default:
          return state;
      }
    }
  );

  async function updateCart(type, item) {
    updateOptimisticCart({ type, item });
    await saveCart({ type, item });
  }

  return (
    <div>
      {optimisticCart.map(item => (
        <div key={item.id}>
          {item.name} - ${item.price}
          <button onClick={() => updateCart('remove', item)}>Remove</button>
        </div>
      ))}
    </div>
  );
}

Contoh 5: Tetapan Pengguna Optimis

function UserSettings() {
  const [settings, setSettings] = useState({});
  const [optimisticSettings, updateOptimisticSetting] = useOptimistic(
    settings,
    (state, update) => ({
      ...state,
      [update.key]: update.value
    })
  );

  async function updateSetting(key, value) {
    updateOptimisticSetting({ key, value });
    await saveSettings({ [key]: value });
  }

  return (
    <div>
      <div>
        <label>
          Theme:
          <select 
            value={optimisticSettings.theme} 
            onChange={e => updateSetting('theme', e.target.value)}
          >
            <option value="light">Light</option>
            <option value="dark">Dark</option>
          </select>
        </label>
      </div>
      <div>
        <label>
          Notifications:
          <input 
            type="checkbox"
            checked={optimisticSettings.notifications}
            onChange={e => updateSetting('notifications', e.target.checked)}
          />
        </label>
      </div>
    </div>
  );
}

Ingat untuk menyemak dokumentasi React rasmi untuk mendapatkan maklumat terkini dan amalan terbaik apabila menggunakan cangkuk ini dalam aplikasi anda.

Selamat Pengekodan!

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