What is the prototype chain in JavaScript?
Each object has a prototype, which is another object. When you access a property, JS looks on the object, then its prototype, then up the chain until found or reaching null. This is how inheritance works in JS without classes.
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More FAQs in FAANG-Level JavaScript Interview Questions With Explanations
The event loop processes the call stack, then microtasks (promise callbacks), then macrotasks (setTimeout, events), one per loop. Microtasks run after each task and before the next macrotask, which is why promise callbacks run before setTimeout callbacks.
It does not run immediately. The callback goes to the macrotask queue and runs after the current stack and all microtasks (promise callbacks) complete. setTimeout 0 defers to the next event loop tick, not to the current one.
call and apply call a function with a specific this and arguments (apply takes an array). bind returns a new function with this permanently set. All three are about controlling this explicitly, which is useful when this matters.
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