Systems-Level CS in the Browser: A Frontend Engineer's Guide to Reconciliation, the Event Loop, Race Conditions & Hashing

A 40-question deep dive built to help frontend engineers better understand algorithms by grounding classic computer-science ideas in browser behavior you can actually observe. Four systems-level topics: the Virtual DOM as a tree-diff algorithm (reconciliation heuristics, list keys, Myers diff), the event loop as a scheduling problem (micro- vs. macro-tasks, requestAnimationFrame, task starvation, cooperative yielding), client-side race conditions and cancellation (out-of-order responses, stale closures, AbortController), and identity, equality & hashing (=== vs. value equality, structural sharing, content hashes). Every "predict the output" answer was executed in Node to confirm it, and every answer links to MDN, the React docs, Wikipedia, or a primary source so you can verify it yourself.