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JavaScript

16 posts
  1. The Senior Frontend Engineer's Field Guide to the DOM and JavaScript Engine InternalsA hands-on, verified tour of what actually happens between your JavaScript and the pixels on screen: the rendering pipeline, live vs static collections, the event loop's real ordering guarantees, layout thrashing, Web Components, and a working virtualized 100,000-row data grid — built and checked in a real browser.JavaScriptDOM41 min
  2. The Frontend Engineer's LeetCode Blueprint, Part 5: The Grandmaster's ToolkitSmall constraints like N ≤ 16 are a signal, not a gift. The finale covers bitmask backtracking with N-Queens, bitmask DP for shortest-path-visiting-all-nodes, and the 60-minute Toptal/Codility survival protocol.JavaScriptFrontend11 min
  3. The Frontend Engineer's LeetCode Blueprint, Part 4: The Dynamic Programming Vault & String AutomatauseMemo and Reselect are dynamic programming with different names. Part 4 covers top-down versus bottom-up DP, the 0/1 knapsack pattern, Edit Distance, and a Trie-backed Word Search II solver.JavaScriptFrontend12 min
  4. The Frontend Engineer's LeetCode Blueprint, Part 3: Trees, Graphs and Solution SpacesThe virtual DOM, AST transpilation and bundler dependency resolution are all tree and graph traversal in production. Part 3 covers post-order tree recursion, topological sort and binary search on the answer space.JavaScriptFrontend12 min
  5. The Frontend Engineer's LeetCode Blueprint, Part 2: The Pointer & Memory PlaygroundReact Fiber and the DOM tree are linked lists in disguise. Part 2 covers fast-and-slow pointers, in-place reversal, the monotonic stack and a from-scratch LRU cache built on a doubly linked list plus hash map.JavaScriptFrontend11 min
  6. The Frontend Engineer's LeetCode Blueprint, Part 1: The Linear GauntletFrontend habits like map/filter/reduce chains fail LeetCode's hidden test suites. Part 1 covers V8 array internals, two pointers and sliding windows, with worked solutions for 3Sum, Minimum Window Substring and Trapping Rain Water.JavaScriptFrontend12 min
  7. The Senior Frontend Engineering Blueprint, Part 7: Building a Linear-Time Query Language ParserEvery product with a power-user search box eventually needs a real query language, and reaching for new RegExp(userInput) is how you end up hand-rolling a vulnerability. Here is a filter-query DSL built from a sticky-regex tokenizer, a recursive-descent parser, and a recursive Zod schema — with a ReDoS stress test to prove the O(N) claim.JavaScriptArchitecture11 min
  8. The Senior Frontend Engineering Blueprint, Part 6: Regex Engines, ReDoS and Defending Untrusted InputA validation regex that passes code review can still be an O(2^n) time bomb. Here is how V8's regex engine actually backtracks, the exact shape of pattern that wedges it, and the rest of the perimeter — Zod pipelines, parameterised SQL, DOMPurify, CSP — that a Next.js app needs around untrusted input.JavaScriptPerformance12 min
  9. Senior Frontend Interview Prep, Part 7: Specification Quirks and CoercionThe last ten questions in the JavaScript volume: ToPrimitive traced step by step, why `[] == ![]` is true, the four equality algorithms, `NaN` and `-0`, BigInt, and the ASI rule that silently eats a return value.JavaScriptFrontend9 min
  10. Senior Frontend Interview Prep, Part 6: Async, Promises, Workers and Shared MemoryFifteen questions on concurrency: promise internals, what `await` desugars to, cancellation that actually cancels, transferables and zero-copy, `SharedArrayBuffer` under cross-origin isolation, and a task pool you can paste into production.ConcurrencyJavaScript12 min
  11. Senior Frontend Interview Prep, Part 5: The Object Model, Prototypes and MetaprogrammingFifteen questions on what an object really is: prototype chains, property descriptors, what `class` desugars to, prototype pollution with a working exploit, and why `Proxy` and private fields do not get along.JavaScriptFrontend13 min
  12. Senior Frontend Interview Prep, Part 4: Scope, Closures and the Temporal Dead ZoneFifteen questions on execution contexts and environment records: what the TDZ actually is, why `let` in a loop works, how `bind` is implemented, and why one `eval` deoptimises every identifier around it.JavaScriptFrontend11 min
  13. Senior Frontend Interview Prep, Part 3: The Event Loop, Scheduling and Paint TimingFifteen questions on what actually runs next: microtasks against macrotasks, the rendering opportunity, libuv's phases, the nextTick ordering rule that has an exception nobody mentions, and how to break up a long task without hurting INP.JavaScriptBrowser10 min
  14. Senior Frontend Interview Prep, Part 2: Memory, Garbage Collection and Leak TopologiesFifteen interview questions on the V8 heap: generational collection, the scavenger, concurrent marking and write barriers, and the five leak shapes behind almost every 'the tab is using two gigabytes' report.MemoryJavaScript12 min
  15. Senior Frontend Interview Prep, Part 1: Inside the JavaScript EngineFifteen interview questions on how V8 turns source text into machine code — tiers, hidden classes, inline caches, elements kinds and deoptimisation — with the answers verified against a live engine.JavaScriptV812 min
  16. Cracking the Staff & Architect Frontend Interview: The Battle-Tested PlaybookStaff and architect interviews are not coding tests — they are risk-assessment conversations. Here are the seven technical pillars that decide the outcome, with the mechanics underneath each one.JavaScriptArchitecture19 min