Thread by @swapnakpanda

JavaScript Interview Questions

⇩

Series: ➌
Level: Beginner
Topics:

➊ Functions - Basics
➋ Function Scope
➌ Function Arguments
➍ Anonymous Functions
➎ Higher Order Function & Callbacks
➏ Closure
➐ IIFE
➑ Arrow Functions

🚥 Disclaimer

⬖ The questions covered here are mostly conceptual.
⬘ I never claim only these type of questions are/should be asked during interviews.
⬗ For interviews, you should have fundamentals strong. And you should be able to provide solutions to practical problems.

➊ Functions - Basics

➀ Can a function name be used like a normal variable?

➁ What is the difference between "myFunction" and "myFunction()"?

➂ Does every function in JS return something even if not explicitly stated? If yes, what does it return by default?

➋ Function Scope

➀ What is a function scope?
➁ How does hoisting work inside a function body?
➂ Among var, let and const, which one does support hoisting?

➌ Function Arguments

➀ What is the difference between function parameters and function arguments?

➁ What is "arguments" reference inside a function body? What purpose does it solve?

➂ Is "arguments" an array? Explain its behaviour.

➃ What is a "Variadic Function"?

➄ What are different ways to access variable number of arguments passed to a function inside its body?

➅ What is a rest parameter operator? How does it work inside function's parameters list?

➆ Define some valid and invalid use cases of rest parameter?

➇ Define significant differences between "arguments" and "a rest parameter".

➍ Anonymous Functions

➀ What are different ways of defining a function?
➁ What is an anonymous function?
➂ Where will an anonymous function be useful? Give some examples of valid use cases.

➃ What is the difference between
❍ function a() {}
❍ let a = function() {}

➄ Are all JavaScript function declarations hoisted?

➎ Higher Order Function & Callbacks

➀ What is a callback function?
➁ Highlight some use cases for callback functions?
➂ Mention few in-built functions that accepts a callback.
➃ What is a higher order function (HOF)?

➏ Closure

➀ Define what is a closure.
➁ When does JavaScript create a closure?
➂ What is a lexical scope?
➃ Define various scopes within a closure.
➄ Why do you think closure is useful?
➅ Highlight few disadvantages of closures.

➐ IIFE

➀ What is IIFE?
➁ Highlight some use cases of IIFE.
➂ Why do we see less usage of IIFE these days? What are its alternatives?

➑ Arrow Functions

➀ What is an arrow function?

➁ Which ES version introduced arrow function?

➂ Given a normal function, convert it into an arrow function.

➃ When is it not mandatory to include arguments inside ( and ) in an arrow function?

➄ When does an arrow function return implicitly even if no return keyword is specified?

➅ What are some key differences between a normal and an arrow function?

⚠️ Repost Notice ⚠️

⬖ Though this is my original work, it was previously posted in [CHIRPBIRDICON]

⬘ Many questions have been taken from the original 🧵

⬙ If you liked these questions and do feel others might learn from it, please support.

End of 🧵

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