NEW QUESTION :-ninja-level JavaScript questions

[Nsanjayboruds]

Hi team,

I’d like to add a new section of ninja-level JavaScript questions for advanced learners and interview prep. These questions are tricky, edge-case, or uncommon topics that even experienced developers often get wrong.

Some example questions I propose:

1. Why does console.log(a); var a = 10; print undefined? Explain hoisting.
2. Explain why [] == ![] evaluates to true.
3. Difference between NaN === NaN and Object.is(NaN, NaN).
4. What will for(var i=0;i<3;i++){ setTimeout(()=>console.log(i),1000); } print and why?
5. Explain why typeof null returns "object".
6. What will console.log([] + {}) print? Why?
7. Explain sparse arrays like: let a=[1,2,3]; a[10]=99; console.log(a.length);

I can contribute a full list of 20–30 ninja-level JS questions with explanations for the repo if approved.

Thanks!

[ganqqwerty]

go ahead!

[Nsanjayboruds]

thank you