Blog

What an index physically is, how B-trees make lookups logarithmic, composite index ordering, covering and partial indexes, reading EXPLAIN ANALYZE, index types beyond the B-tree, adding indexes safely in production, and the query patterns that silently refuse to use your index.

require vs import isn't just syntax — it's dynamic vs static, copies vs live bindings, sync vs async. A field guide to the module systems and the interop errors between them.

How DOM events really travel — capture, target, bubble — and how delegation exploits bubbling to handle a thousand rows with a single listener.

Reachability, generational GC, and the four leak patterns that survive garbage collection — timers, detached DOM nodes, growing caches, and forgotten listeners.

How load balancers decide where each request goes — the classic algorithms, L4 vs L7, health checks, and the sticky-session problem that pushes state out of your servers.

LIFO and FIFO look trivial until you notice they power your call stack, undo history, browser navigation, and every BFS. Plus the classic interview patterns for each.

Build systems, package managers, and course schedulers all answer the same question: what order satisfies every dependency? Kahn's algorithm answers it — and detects impossible cycles.

The disjoint set union structure answers 'are these two connected?' in near-O(1) — with two optimizations you can write in twenty lines. Includes Kruskal's MST and cycle detection.

Why `hash % N` falls apart the moment you add a server, how consistent hashing moves only a fraction of your keys when the cluster changes, virtual nodes, replicas on the ring, bounded loads, rendezvous and jump hashing, and what Cassandra and Redis Cluster actually do.

The protocol behind for...of, the spread operator, and async/await — plus generator functions, which can pause mid-execution and resume exactly where they left off.