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2024 Ultimate Guide to JavaScript Interview Questions and Answers

M Mainul Hasan on January 11, 2024

JavaScript is a dynamic language, essential in web development and increasingly important in other areas of software development. This guide compil...
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Jon Randy 🎖️ • Edited

You've omitted BigInt and Symbol from the primitive types.

Also, your answer to "What is a Closure?" is not really correct:

A function that remembers its outer scope, enabling data hiding

The problems with the answer are that ALL functions remember their outer scope, and that a closure isn't a function:

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Jon Randy 🎖️ • Edited

Variables declared outside functions are accessible anywhere.

This isn't correct. Variables can also be declared inside modules, and inside blocks - both of which are/can be outside of functions, but are not accessible anywhere.

Variables declared within a function are accessible only inside it.

This can also apply to modules and blocks.

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M Mainul Hasan

🌟 Thank you for your insightful comment! I agree that the scope of a variable declaration in JavaScript goes beyond just functions, extending to modules and blocks as well.

As I mentioned,

Variables declared outside functions are accessible anywhere

and

Variables declared within a function are accessible only inside it

my focus was on illustrating the basic concept of global and local scope in functions.

Indeed, in JavaScript, the concept of scope extends beyond just functions. Variables declared in modules or blocks (like those inside if statements or loops) have their unique scopes.

For instance, let or const declarations confine a variable declared inside a block to that block, and it is not accessible outside of it, which aligns with the block-scoping nature of these declarations.