React component re-rendering unexpectedly when using useMemo with complex objects
I'm having trouble with I've hit a wall trying to I'm stuck trying to After trying multiple solutions online, I still can't figure this out... I'm facing an issue with my React component that uses `useMemo` to avoid unnecessary re-renders, but I'm still seeing unexpected re-renders when I update the state. The goal is to memoize a derived state based on a complex object, but it doesn’t seem to work as I expected. Here’s a simplified version of my code: ```javascript import React, { useState, useMemo } from 'react'; const MyComponent = ({ data }) => { const [count, setCount] = useState(0); const memoizedValue = useMemo(() => { // Simulate a complex calculation based on data return data.map(item => ({ ...item, processed: true })); }, [data]); const handleClick = () => { setCount(prevCount => prevCount + 1); }; return ( <div> <h1>{count}</h1> <button onClick={handleClick}>Increment</button> <pre>{JSON.stringify(memoizedValue, null, 2)}</pre> </div> ); }; export default MyComponent; ``` I noticed that every time I click the button to increment the count, the `memoizedValue` seems to be recalculated, even though the `data` prop hasn’t changed. I expected `useMemo` to return the cached result unless `data` changed. The `data` prop is an array of objects that comes from a parent component, and it’s updated only when a specific condition is met. I’m using React 18.0.0. I've also tried using `React.memo` for `MyComponent`, but that didn’t help either. The console shows that `memoizedValue` is recalculated every time the state changes, and I’m getting these logs: ``` Recalculating memoized value... Recalculating memoized value... ``` How can I ensure that `memoizedValue` only recalculates when `data` changes? What am I missing? I'm developing on CentOS with Javascript. I'd be grateful for any help. What's the best practice here? For context: I'm using Javascript on Windows 10.