Engine Internals

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1. 01 Explain the Global Execution Context vs Function Execution Context. Medium
2. 02 What are the two phases of execution context creation (memory creation and code execution)? Hard
3. 03 Explain the Lexical Environment and Environment Record and how they relate to closures. Hard
4. 04 How does the JS engine manage the execution context stack when a function calls another function? Medium
5. 05 Trace the execution context stack for a small recursive function computing factorial(3). Medium
6. 06 Explain the difference between the Variable Environment and Lexical Environment inside an execution context. Hard
7. 07 How does `this` binding get determined during execution context creation? Medium
8. 08 What is the call stack and how does it grow/shrink as functions call each other? Easy
9. 09 Explain 'Maximum call stack size exceeded' and demonstrate how unbounded recursion triggers it. Medium
10. 10 What is tail call optimization? Why isn't it broadly implemented across JS engines despite being in the spec? Hard
11. 11 Rewrite a recursive factorial function to be tail-call friendly and discuss real-world engine support. Hard
12. 12 How does async/await interact with the call stack differently from synchronous recursive calls? Hard
13. 13 Explain how a stack trace helps you debug deep call chains in DevTools. Easy
14. 14 Explain the JavaScript memory lifecycle: allocation, use, and release. Medium
15. 15 What are the four common causes of memory leaks in frontend JavaScript applications? Medium
16. 16 How do detached DOM nodes cause memory leaks, and how would you detect them using Chrome DevTools heap snapshots? Hard
17. 17 Explain how closures can unintentionally retain large objects in memory. Medium
18. 18 What is the difference between the stack and the heap for memory allocation in JS? Medium
19. 19 How do global variables and forgotten timers/intervals contribute to memory leaks in single-page apps? Medium
20. 20 Explain WeakRef and FinalizationRegistry — what problems do they solve, and why should they be used cautiously? Hard
21. 21 Explain the mark-and-sweep algorithm used by JS engines for garbage collection. Medium
22. 22 What is reference counting garbage collection and why does it fail with circular references? Medium
23. 23 Explain V8's generational garbage collection (young generation / old generation, Scavenger, Mark-Compact). Hard
24. 24 How does garbage collection affect JS performance, and what strategies help minimize GC pauses in hot code paths? Hard
25. 25 Explain why object pooling can help reduce garbage collection pressure in performance-critical applications (e.g., games, canvas rendering). Hard