👀 Views: 12 💬 Answers: 1 📅 Created: 2025-08-25

react javascript state-management

I'm migrating some code and I'm attempting to set up I'm working with a strange scenario with how I'm updating an array in my React component state. I'm using the spread operator to create a new array based on the previous state, but it seems to be referencing the original array instead of creating a copy. This is leading to unexpected behaviors, particularly when I try to modify the new array. Here's a simplified version of my code: ```javascript import React, { useState } from 'react'; const MyComponent = () => { const [items, setItems] = useState([1, 2, 3]); const addItem = (newItem) => { const newItems = [...items]; // Using spread operator newItems.push(newItem); setItems(newItems); }; const updateItem = (index, value) => { const newItems = [...items]; newItems[index] = value; setItems(newItems); }; return ( <div> <button onClick={() => addItem(4)}>Add Item</button> <button onClick={() => updateItem(0, 10)}>Update First Item</button> <div>{JSON.stringify(items)}</div> </div> ); }; export default MyComponent; ``` The `addItem` function seems to work fine, as it adds the new item correctly. However, when I try to update an item using `updateItem`, it doesn’t seem to reflect the changes as I expect. The first item is modified in the state, but the component doesn't re-render with the new value. I'm not seeing any errors in the console but the array in the UI does not update accordingly. I've tried a couple of debugging strategies: - Logging `newItems` after each modification. - Checking if the state is being updated correctly with `items` and `newItems`. I even tested with different versions of React (including v17 and v18), and the scenario continues. Some colleagues suggested that it might be related to how React batches state updates. However, I'm not sure how to resolve it correctly. Any help would be greatly appreciated! I appreciate any insights! I'm working with Javascript in a Docker container on Windows 11. Am I missing something obvious? I'm on Windows 10 using the latest version of Javascript. My development environment is Windows 10. Any advice would be much appreciated.