React Reconciliation: The Virtual DOM Diff
React diffs a lightweight in-memory tree against the next render to apply only surgical changes to the real DOM. It fires on every state or prop change. Missing keys in lists force React to rebuild more nodes than needed, destroying performance.
React maintains a lightweight in-memory copy of your UI called the Virtual DOM. When state or props change, it builds a new tree, diffs it against the old one via reconciliation, and computes the smallest set of real DOM mutations. This avoids wiping and redrawing the entire page every time a component re-renders from a user click or data fetch. The common footgun is omitting stable keys in lists, which makes React treat identical items as changed and rebuild far more than necessary.
Read the original → direct-llm://reconciliationandthevirtualdom
- #react
- #virtual-dom
- #reconciliation
- #performance
- #rendering
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