Thread by @swapnakpanda

🤷‍♀️ JavaScript Interview Questions (Series 3)

👉 A detailed coverage on functions

👇

Before proceeding, do check the previous one of this series 👇

https://twitter.com/swapnakpanda/status/1456878460748513284?s=20

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.

Series: 3️⃣
Level: Beginner
Topics:

1️⃣ Functions - Basics
2️⃣ Function Scope
3️⃣ Function Arguments
4️⃣ Anonymous Functions
5️⃣ Higher Order Function & Callbacks
6️⃣ Closure
7️⃣ IIFE
8️⃣ Arrow Functions

1️⃣ Functions - Basics

✪ Can a function name be used like a normal variable?
✪ What is the difference between evaluating "myFunction" and "myFunction()"?
✪ Does every function in JS return something even if not explicitly stated? If yes, what does it return by default?

2️⃣ Function Scope

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

3️⃣ Function Arguments

✪ What is the difference between function parameters and function arguments?
✪ What is "arguments" reference inside a function body? What purpose does it solve?
✪ Is "arguments" an array? Explain its behaviour.

✪ What is a "Variadic Function"?
✪ What are different ways to access variable number of arguments passed to a function inside its body?
✪ What is a rest parameter operator? How does it work inside function's parameters?

✪ Define some valid and invalid use cases of rest parameter?
✪ Define significant differences between "arguments" and "a rest parameter".

4️⃣ Anonymous Functions

✪ What are different ways of defining a function?
✪ What is an anonymous function?
✪ Where will an anonymous function be useful?
✪ What is the difference between "function a() {}" and "let a = function() {}"?
✪ Are all JavaScript functions hoisted?

5️⃣ Higher Order Function & Callbacks

✪ What is a callback function?
✪ Highlight some use cases for callback functions?
✪ Mention few in-build functions that accept a callback.
✪ What is a higher order function (HOF)?

6️⃣ Closure

✪ Define what is a closure.
✪ When does JavaScript create a closure?
✪ What is a lexical scope?
✪ Define various scopes within a closure.
✪ Why do you think closure is useful?
✪ Highlight few disadvantages of closures.

7️⃣ IIFE

✪ What is IIFE?
✪ Highlight some use cases of IIFE.
✪ The usage of IIFE has been reduced. Why? What are its alternatives?

8️⃣ Arrow Functions

✪ What is an arrow function?
✪ Which ES version introduced arrow function?
✪ Given a normal function, convert it into an arrow function.
✪ When is it not mandatory to include arguments inside ( and ) in an arrow function?

✪ When does an arrow function return implicitly even if no return keyword is specified?
✪ What are some key differences between a normal and an arrow function?

The next 🧵 of this series will provide questions from

1️⃣ Array
2️⃣ String

I am sharing "Interview Questions" for few other subjects. Find all of them 👇

https://twitter.com/swapnakpanda/status/1456599023704436744?s=20

Are you interested in SQL? 👇 is an introductory to SQL commands. Do check and if found useful, please support.

https://twitter.com/swapnakpanda/status/1459504163159564294