Tagged with performance
JavaScript uses garbage collection, but leaks still happen when references stay alive unexpectedly or when code creates unnecessary work.
Garbage collection, memory leaks, deep copy vs shallow copy, and performance pitfalls in loops and DOM updates
Initial render and later re-renders follow different triggers, and where state lives strongly affects how much of the tree must update.
Parent vs child re-renders, initial render, re-renders, and state colocation
React apps become slow when they re-render too much, do expensive work in render, or ship more code and DOM than needed.
React performance: slow apps, unnecessary re-renders, React.memo, PureComponent, code splitting, lazy loading, Suspense, virtualization, profiling, and bundle size
React memoization tools help avoid unnecessary work, but they only help when they stabilize expensive calculations or props meaningfully.
useMemo, useCallback, React.memo, and memoization in React
React compares virtual tree snapshots, reconciles differences, and updates the real DOM only where needed.
Virtual DOM, reconciliation, diffing, and why React feels fast
Limit parsed columns, set dtypes intentionally, and stream large files in chunks when needed.
read_csv performance tips in pandas
Vectorization means using array-style operations on whole columns instead of Python loops over rows.
What does vectorization mean in pandas?
Cache expensive work at the right layer: low-level data, per-view output, or template fragments.
Django caching basics
Use relation-aware loading like select_related and prefetch_related when templates or loops will touch related objects repeatedly.
How do you avoid N+1 queries in Django?
select_related joins single-valued relations in SQL; prefetch_related fetches related collections in extra queries.
select_related vs prefetch_related