Handling Multiple Event Listeners on a Single Element in React - Performance Issues
I'm following best practices but Does anyone know how to This might be a silly question, but I'm encountering performance issues with a React component where I need to register multiple event listeners on a single DOM element... The component is supposed to handle mouse events for drag-and-drop functionality as well as keyboard events for accessibility. However, when I add event listeners inside the `useEffect` hook, I notice that the component re-renders excessively, leading to degraded performance. Here's a simplified version of what I'm doing: ```javascript import React, { useEffect } from 'react'; function DraggableComponent() { const handleMouseDown = (e) => { // Start dragging }; const handleMouseMove = (e) => { // Handle dragging }; const handleKeyPress = (e) => { if (e.key === 'Enter') { // Trigger action on enter } }; useEffect(() => { const element = document.getElementById('draggable'); element.addEventListener('mousedown', handleMouseDown); element.addEventListener('mousemove', handleMouseMove); window.addEventListener('keypress', handleKeyPress); return () => { element.removeEventListener('mousedown', handleMouseDown); element.removeEventListener('mousemove', handleMouseMove); window.removeEventListener('keypress', handleKeyPress); }; }, []); return <div id='draggable' style={{ width: '100px', height: '100px', backgroundColor: 'blue' }} />; } ``` Initially, I was using a separate `useEffect` for each event listener, but the excessive re-renders seem to stem from how I'm handling dependencies. The performance drops significantly when I interact with the element, especially when dragging. When I log the number of renders, it sometimes exceeds 50 in just a few seconds. I’ve tried using `useCallback` to memoize the event handler functions, but it didn’t help much. I also considered moving the event handling logic outside of the component, but that would complicate state management due to React’s lifecycle. Any advice on optimizing this setup or alternative patterns for managing multiple event listeners would be greatly appreciated. I’m using React 17.0.2 and testing in Chrome 93, with a focus on performance best practices. My development environment is Windows. Am I missing something obvious? Any ideas what could be causing this? This is part of a larger desktop app I'm building. What am I doing wrong? For reference, this is a production mobile app.