React 18: How to Prevent Unnecessary Re-renders When Using useMemo with Complex Objects
Can someone help me understand I tried several approaches but none seem to work. I'm working on a React 18 application where I need to optimize performance by preventing unnecessary re-renders. I have a component that uses `useMemo` to memoize a complex object, but I'm still noticing that the component re-renders more often than expected. Here’s a simplified version of the code that illustrates the issue: ```javascript import React, { useMemo, useState } from 'react'; const ComplexComponent = ({ data }) => { const [count, setCount] = useState(0); const memoizedValue = useMemo(() => { return { transformedData: data.map(item => item * 2), timestamp: Date.now() }; }, [data]); console.log('Component rendered'); return ( <div> <button onClick={() => setCount(count + 1)}>Increment Count</button> <div>Count: {count}</div> <div>{JSON.stringify(memoizedValue)}</div> </div> ); }; export default ComplexComponent; ``` In this example, even when the `data` prop doesn't change, the component still re-renders whenever I click the button to increment the count. The `memoizedValue` is being recalculated every time because I'm using `Date.now()` in the object. This makes it seem like `memoizedValue` is a new object even if `data` hasn't changed. I tried refactoring to only return `transformedData` without the timestamp, but I need the timestamp for other logic in my app. I also considered using `useRef` for the timestamp, but it doesn't seem to fit well with how I'm currently using `useMemo`. Is there a way to keep the memoized object stable while still including the timestamp? Or should I approach this optimization differently? Any insights would be greatly appreciated! For context: I'm using Javascript on macOS. What am I doing wrong?