What is the temporal dead zone in JavaScript?
The period between entering a scope and the actual declaration of a let or const variable. let and const are hoisted but not initialized, so accessing them before declaration throws a ReferenceError, unlike var which is undefined.
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More FAQs in Common Mistakes Candidates Make in JavaScript Interviews
Because interviewers ask follow-ups that expose it. Reciting a definition does not help with 'why does this happen' or 'show me an example' follow-ups. Understand the reasoning behind each concept, not just the words.
Because this depends on how a function is called, not where it is defined, and arrow functions do not have their own this. Confusing this shows in any question about callbacks or class-like patterns, which is most non-trivial JS.
Because it is core to how JS works on a single thread, and it explains async behavior. Treating JS as multithreaded or not understanding microtask vs macrotask ordering signals weak fundamentals, which interviewers catch.
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