02/06/2026
Stop using index as a key in your React lists.
Why it’s breaking your UI:
When rendering a dynamic list in React, it’s tempting to just grab the array index and pass it as a key:
map((item, index) => )
Why this is dangerous:
React relies on keys to track which items have changed, been added, or been removed in the Virtual DOM. If your list shifts, filters, or re-orders, the index changes—but the data doesn't. This confuses React's reconciliation engine, leading to weird rendering bugs, broken form inputs, and sluggish performance.
The Correct Approach:
Always use a unique identifier from your data (like an item.id) as the key.
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