Buglyst Blog
Learn to debug under pressure.
Playbooks for fast pattern recognition, guides for the full investigation, and articles for the engineering judgment around the edges.
17 playbooks · 509 guides · 95 articles · 12 linked practice labs ·skip to practice
Fast pattern recognition for the production failures engineers see most often.
1 playbook in Languages & Runtime
Structured investigations for the failure modes engineers meet in real systems.
Debugging TypeScript Generic Type Constraint Errors
A practical guide to diagnosing and fixing TypeScript errors when generic type parameters violate their constraints, with real-world debugging strategies and a war story.
Mapped Types Returning 'never' or 'unknown' — What Your IDE Won't Tell You
A field guide for when mapped types silently collapse to 'never' or 'unknown', covering conditional checks, key remapping, and distributive conditional types.
JavaScript Closure Stale Variable Inside Loop
A debugging guide for the classic JavaScript closure-in-loop bug where callbacks capture the final value of a loop variable instead of each iteration's value.
TypeScript Discriminated Union Type Narrowing Not Working
A practical debugging guide for when TypeScript's discriminated union type narrowing fails due to common pitfalls like excess property checks, optional discriminants, and type assertions.
Debugging Prototype Chain Inheritance Bugs in JavaScript
A guide to diagnosing and fixing subtle bugs caused by shared state and unintended property shadowing in JavaScript prototype chains.
JavaScript Microtask & Promise Execution Order Debugging
A deep dive into debugging broken promise execution order and microtask queue race conditions in Node.js and browser environments.
Long-form thinking on debugging habits, observability, and the systems around the bug.