React experimental_Activity 状态：精通组件活动状态跟踪

            import React, { useState, useEffect, experimental_Activity, use } from 'react';

const fetchData = async () => {
  // Simulate API call
  return new Promise(resolve => setTimeout(() => resolve([{ id: 1, name: 'Product 1' }, { id: 2, name: 'Product 2' }]), 2000));
};

function ProductList() {
  const activity = experimental_Activity.createActivity('Fetching Products');
  const [products, setProducts] = useState(null);
  const [error, setError] = useState(null);
  const activityState = experimental_Activity.useActivityState(activity);

  useEffect(() => {
    experimental_Activity.startActivity(activity);

    fetchData()
      .then(data => {
        setProducts(data);
        experimental_Activity.completeActivity(activity);
      })
      .catch(err => {
        setError(err);
        experimental_Activity.cancelActivity(activity);
      });
  }, []);

  if (activityState.state === 'pending' || activityState.state === 'running') {
    return <p>Loading products...</p>;
  }

  if (error) {
    return <p>Error: {error.message}</p>;
  }

  return (
    <ul>
      {products.map(product => (
        <li key={product.id}>{product.name}</li>
      ))}
    </ul>
  );
}

export default ProductList;

            

              
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            import React, { useState, experimental_Activity } from 'react';

function ContactForm() {
  const submitActivity = experimental_Activity.createActivity('Submitting Form');
  const [formData, setFormData] = useState({
    name: '',
    email: '',
    message: '',
  });
  const [isSubmitting, setIsSubmitting] = useState(false);
  const submitActivityState = experimental_Activity.useActivityState(submitActivity);

  const handleChange = (e) => {
    setFormData({ ...formData, [e.target.name]: e.target.value });
  };

  const handleSubmit = async (e) => {
    e.preventDefault();

    experimental_Activity.startActivity(submitActivity);
    setIsSubmitting(true);

    // Simulate form submission
    await new Promise(resolve => setTimeout(resolve, 3000));

    experimental_Activity.completeActivity(submitActivity);
    setIsSubmitting(false);
    alert('Form submitted successfully!');
  };

  return (
    <form onSubmit={handleSubmit}>
      <label>
        Name:
        <input type="text" name="name" value={formData.name} onChange={handleChange} />
      </label>
      <br />
      <label>
        Email:
        <input type="email" name="email" value={formData.email} onChange={handleChange} />
      </label>
      <br />
      <label>
        Message:
        <textarea name="message" value={formData.message} onChange={handleChange} />
      </label>
      <br />
      <button type="submit" disabled={submitActivityState.state === 'running'}>
        {submitActivityState.state === 'running' ? 'Submitting...' : 'Submit'}
      </button>
    </form>
  );
}

export default ContactForm;

            

              
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            import React, { Suspense, experimental_Activity, use } from 'react';

const fetchData = async () => {
  // Simulate API call
  return new Promise(resolve => setTimeout(() => resolve([{ id: 1, name: 'Product 1' }, { id: 2, name: 'Product 2' }]), 2000));
};

const Resource = {
  read: () => {
      const activity = experimental_Activity.createActivity('Fetching resource');
      experimental_Activity.startActivity(activity);
      let result;

      const promise = fetchData()
        .then(data => {
            result = data;
            experimental_Activity.completeActivity(activity);
        })
        .catch(err => {
            experimental_Activity.cancelActivity(activity);
            throw err;
        });

      if (!result) {
        throw promise;
      }

      return result;
  }
}

function ProductList() {
  const products = use(Resource.read());

  return (
    <ul>
      {products.map(product => (
        <li key={product.id}>{product.name}</li>
      ))}
    </ul>
  );
}

function App() {
  return (
    <Suspense fallback={<p>Loading products...</p>}>
      <ProductList />
    </Suspense>
  );
}

export default App;

            

              
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