React experimental_useEffectEvent：掌握事件处理程序清理，防止内存泄漏

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

function MyComponent() {
  const [count, setCount] = useState(0);

  useEffect(() => {
    const handleClick = () => {
      setTimeout(() => {
        setCount(count + 1); // Potential stale closure
      }, 1000);
    };

    window.addEventListener('click', handleClick);

    return () => {
      window.removeEventListener('click', handleClick);
    };
  }, []);

  return 
Count: {count}
;
}

export default MyComponent;

            

              
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import React, { useState, useEffect, experimental_useEffectEvent } from 'react';

function MyComponent() {
  const [count, setCount] = useState(0);

  const handleClick = experimental_useEffectEvent(() => {
    setTimeout(() => {
      setCount(prevCount => prevCount + 1); // Use functional update
    }, 1000);
  });

  useEffect(() => {
    window.addEventListener('click', handleClick);

    return () => {
      window.removeEventListener('click', handleClick);
    };
  }, [handleClick]); // Depend on handleClick

  return 
Count: {count}
;
}

export default MyComponent;

            

              
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import React, { useState, useEffect, experimental_useEffectEvent } from 'react';
import { CustomEventEmitter } from './custom-event-emitter';

function MyComponent() {
  const [message, setMessage] = useState('');

  const handleEvent = experimental_useEffectEvent((data) => {
    setMessage(data.message);
  });

  useEffect(() => {
    CustomEventEmitter.addListener('customEvent', handleEvent);

    return () => {
      CustomEventEmitter.removeListener('customEvent', handleEvent);
    };
  }, [handleEvent]);

  return 
Message: {message}
;
}

export default MyComponent;

            

              
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import React, { useState, useEffect, experimental_useEffectEvent } from 'react';

function MyComponent() {
  const [coordinates, setCoordinates] = useState({ x: 0, y: 0 });

  const handleMouseMove = experimental_useEffectEvent((event) => {
    setCoordinates({ x: event.clientX, y: event.clientY });
  });

  useEffect(() => {
    window.addEventListener('mousemove', handleMouseMove);

    return () => {
      window.removeEventListener('mousemove', handleMouseMove);
    };
  }, [handleMouseMove]);

  return 
Coordinates: ({coordinates.x}, {coordinates.y})
;
}

export default MyComponent;

            

              
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import React, { useState, useEffect, experimental_useEffectEvent } from 'react';

function GlobalEventListenerComponent() {
  const [scrollPosition, setScrollPosition] = useState(0);

  const handleScroll = experimental_useEffectEvent(() => {
    setScrollPosition(window.scrollY);
  });

  useEffect(() => {
    window.addEventListener('scroll', handleScroll);

    return () => {
      window.removeEventListener('scroll', handleScroll);
    };
  }, [handleScroll]);

  return 
Scroll Position: {scrollPosition}
;
}

export default GlobalEventListenerComponent;

            

              
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import React, { useState, useEffect, experimental_useEffectEvent } from 'react';

function AsyncEventHandlerComponent() {
  const [data, setData] = useState(null);

  const fetchData = async (signal) => {
    try {
      const response = await fetch('https://api.example.com/data', { signal });
      const result = await response.json();
      setData(result);
    } catch (error) {
      if (error.name !== 'AbortError') {
        console.error('Fetch error:', error);
      }
    }
  };

  const handleClick = experimental_useEffectEvent(() => {
    const controller = new AbortController();
    fetchData(controller.signal);
    return () => controller.abort(); // Cleanup function to abort fetch
  });

  useEffect(() => {
    return handleClick(); // Call cleanup function immediately on unmount.
  }, [handleClick]);

  return (
    

      Fetch Data
      {data && 
Data: {JSON.stringify(data)}
}
    
  );
}

export default AsyncEventHandlerComponent;

            

              
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import React, { useState, useEffect, experimental_useEffectEvent } from 'react';

function AccessibleButton() {
  const [count, setCount] = useState(0);

  const handleClick = experimental_useEffectEvent(() => {
    setCount(prevCount => prevCount + 1);
  });

  useEffect(() => {
     // No useEffect side effects currently, but here for completeness with the handler
  }, [handleClick]);

  return (
    
      Count: {count}
    
  );
}

export default AccessibleButton;

            

              
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