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Engineering Deep Dives

Practical deep dives on how software works and how teams build it, with the answer up front, a diagram where it helps and sources for every claim.

AI & Engineering9 min read

AI Makes Writing Code Cheaper. It Does Not Make Engineering Judgment Cheaper.

AI assistants cut the cost of producing code, but not of verifying, reviewing and owning it. What the research shows, where the bottleneck moves and how teams should adapt.

  • AI
  • Teams
  • Code Review
Engineering Leadership12 min read

The Metrics That Make Engineering Organizations Worse

Lines of code, story points and pull-request counts reward the wrong behavior. Why vanity metrics backfire, and how to measure outcomes, flow and health without gaming.

  • Teams
  • Metrics
  • Productivity
JavaScript10 min read

Race Conditions in JavaScript: When Single-Threaded Code Is Not Safe

JavaScript runs one thing at a time, yet async code still races. Lost updates, stale responses and double submits, and the patterns that prevent each one.

  • JavaScript
  • Async
  • Concurrency
Engineering Leadership11 min read

Technical Debt Is Not the Enemy. Unpriced Technical Debt Is.

Debt is a tool when you know its cost. How to measure technical debt through change cost, risk and toil, decide what to pay down, and talk about it in terms the business funds.

  • Teams
  • Architecture
  • Maintenance
JavaScript10 min read

From Call Stack to Heap: How JavaScript Manages Memory

Where values live, how the garbage collector decides what to free, why reachability is the only rule that matters, and how to find and fix the leaks it can’t.

  • JavaScript
  • Runtime
  • Performance
Architecture & Systems10 min read

Distributed Systems Fail in the Gaps Between Teams

Most outages start where one team’s service meets another’s. Contracts, timeouts, retries and ownership that stop one slow dependency from taking everything down.

  • Distributed Systems
  • Reliability
  • Architecture
JavaScript8 min read

How Promises and async/await Actually Work

Promise states, chaining, adoption, error propagation and microtask timing, then what async/await compiles to. With the ordering rules and the mistakes they explain.

  • JavaScript
  • Async
  • Runtime
JavaScript9 min read

Scope, Hoisting and the Temporal Dead Zone in JavaScript

The five kinds of scope in JavaScript, how name lookup works, what hoisting really does to var, let, const, functions and classes, and why the temporal dead zone exists.

  • JavaScript
  • Fundamentals
  • Language Internals
Architecture & Systems13 min read

The Architecture Decisions That Matter More Than Your Tech Stack

Coupling, boundaries, data ownership and independent deployment decide how fast a system can change. How to recognize those decisions and make them deliberately.

  • Architecture
  • System Design
  • Teams
JavaScript9 min read

JavaScript’s this Keyword, Four Rules and One Exception

this depends on how a function is called, not where it is written. Four call-site rules, the arrow function exception and how to fix a lost this in callbacks.

  • JavaScript
  • Frontend
  • Fundamentals
JavaScript10 min read

The Event Loop Is Not What You Think: Tasks, Microtasks and Order

How the call stack, task queue, microtask queue and rendering fit together, how to predict execution order, and why a busy loop or a promise chain can freeze the page.

  • JavaScript
  • Runtime
  • Performance
JavaScript7 min read

Why JavaScript Equality Is More Complicated Than == vs ===

JavaScript has four equality algorithms. How == coerces, why NaN and -0 break ===, what Object.is and SameValueZero do, and which one Map, Set and includes use.

  • JavaScript
  • Fundamentals
  • Language Internals
JavaScript7 min read

What Happens When a Function Runs: Execution Contexts and Closures

Execution contexts, lexical environments, the scope chain and closures, explained as one model, with the loop and memory pitfalls it explains.

  • JavaScript
  • Fundamentals
  • Language Internals
JavaScript7 min read

How JavaScript Modules Work: Scope, Live Bindings and Cycles

ES modules and CommonJS load, share and evaluate code differently. Live bindings, singletons, circular imports and the rules that decide what you actually get.

  • JavaScript
  • Modules
  • Node.js
JavaScript7 min read

The Hidden Cost of Mutable State in JavaScript

Aliasing, shallow copies and in-place methods cause bugs that show up far from their cause. How references work, and when to copy, freeze or isolate state.

  • JavaScript
  • Fundamentals
  • State Management
JavaScript8 min read

What Happens When You Read a Property in JavaScript

Property descriptors, getters, setters and the prototype chain explained through one lookup algorithm, with the shadowing rules that surprise people.

  • JavaScript
  • Fundamentals
  • Language Internals