Handling Large Data Sets with useMemo in React - Performance Issues and Stale Data
I'm building a feature where I'm currently working on a React application (React 17) that fetches a large dataset from my Node.js backend... The dataset can contain several thousand entries, and I want to display this data in a table format while ensuring optimal performance. I decided to use `useMemo` to memoize the transformed data to prevent unnecessary recalculations when the component re-renders. However, I'm encountering a problem where the memoized value seems to be getting stale, leading to outdated data being displayed. Here’s a simplified version of my code: ```javascript import React, { useEffect, useMemo, useState } from 'react'; import axios from 'axios'; const DataTable = () => { const [data, setData] = useState([]); const [filter, setFilter] = useState(''); useEffect(() => { const fetchData = async () => { const result = await axios('/api/data'); setData(result.data); }; fetchData(); }, []); const filteredData = useMemo(() => { return data.filter(item => item.name.includes(filter)); }, [data, filter]); return ( <div> <input type='text' value={filter} onChange={e => setFilter(e.target.value)} /> <table> <thead> <tr> <th>Name</th> </tr> </thead> <tbody> {filteredData.map(item => ( <tr key={item.id}> <td>{item.name}</td> </tr> ))} </tbody> </table> </div> ); }; export default DataTable; ``` When I type into the filter input, the table does not update as expected. I checked the console and verified that the `data` state is updating correctly after fetching. However, the `filteredData` does not reflect the latest state unless I refresh the entire component. I also tried using `console.log` statements to trace the values of `data` and `filteredData` at various points, but they seem to indicate that `filteredData` is relying on an old reference to `data` that doesn't update. I've also tried using `useCallback` for the filter function, but that didn't resolve the issue either. Is there something I'm missing in how I'm setting up `useMemo`, or is there a better approach to handle this situation? Any guidance would be appreciated!