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Sample answers to the most common JavaScript interview questions

Sample answers to the most common JavaScript interview questions

JavaScript is a very important scripting language that programmers use to build websites and apps. Because of this, a lot of people who want to work as programmers need to know this language. If you’ve been learning more about JavaScript (JS), you might be looking for a new job as a JS developer. We’ll look at a wide range of interview questions and how to answer them in this article. You can use this to help you find a job.

General questions

As with any job interview, you will be looked at for more than one skill. The person who is interviewing you will want to know a little bit about you and what motivates you at work. Here are some general questions that people whose jobs require them to work with JavaScript might be asked:

  • Why do you want to work someplace else?
  • Where can you find out about the latest news and trends in JS and coding in general?
  • What are the most important skills for a JavaScript programmer to have?
  • What was the best thing about your last job?
  • What did you not like about it?
  • How do you know you can write good code?
  • What are your worst skills at programming?
  • Where do you see yourself in five years?
  • Why should we hire you as our next JS developer?
  • What is the most important thing you’ve done at work?

Questions about work and history from the past

But your interviewer will also want to know how you got to where you are now and if your skills and experience make you a good fit. In the next section, we answer some of the most common questions about background and experience:

  • Using JavaScript, what have you done?
  • What other programming languages do you know?
  • When did you start using JavaScript?
  • What made you want to learn how to code?
  • Are there any languages or ways of coding for which you have a certificate?
  • How did you learn to be a JavaScript programmer? What kind of schooling do you have?
  • Since when have you been a programmer?
  • What’s the most recent programming language you learned?
  • Tell me about a time when you tried to use JavaScript but it didn’t work out. What happened?
  • Talk about the last JavaScript project you did that worked well.

In-depth questions

You will have to show your knowledge in a more specific way at some point, just like you have to do with any skill you’ve worked on. It could make all the difference if you can do this in a way that sounds natural and smart. Here are some more in-depth questions about how to use JavaScript:

  • What’s different about a scripting language from other languages?
  • Write a piece of code in JavaScript.
  • Change some JavaScript code.
  • In JS, what is a “spread operator?”
  • How do I remove duplicates from JS?
  • What is a Promise in JS?
  • What’s the difference between Array.splice() and Array.slice()?
  • How do you do 301 redirects with JS?
  • How do you use the setTimeout function?

Explain the difference between global scope and local scope.

This is just the beginning of where the conversation could go, but the most important thing is to be able to talk in depth about JavaScript in a way that shows skill and ease. Here are some more questions you could be asked:

  • Write down the different kinds of JS errors that can happen.
  • What does it mean in JS for a function to be “anonymous”?
  • What are equality operators?
  • What is the purpose of a scope chain?
  • What do console.time() and console.timeEnd() do?
  • How do you call a function after a certain amount of time has gone by?
  • How do accessors in JS work?
  • What are some popular frameworks for unit testing in JS?
  • Shallow copy is not the same as deep copy.

How to answer questions about JavaScript and how to ask them

Reviewing some sample answers to interview questions will help you get ready for your own. Here are answers to some of the most frequently asked questions about JavaScript:

  • Why is using JS a good idea?
  • What’s the difference between Java and JavaScript?
  • Why does a JS source file need a function block around the code?
  • What is NaN and what does it do?
  • What kinds of information can JavaScript use?
  • Which, JavaScript or ASP, is faster, and why?
  • Describe variables that haven’t been set or haven’t been declared.

Why is using JS a good idea?

By answering this question, you can show that you know what JavaScript is and why developers need it. JavaScript has a lot of good points. Some of them are:

  • Learning how to use JavaScript isn’t too hard.
  • It is a language that runs on the client, not on the server.
  • JS is quick.
  • It doesn’t require a compiler.
  • It is pretty easy to test and fix bugs.
  • It is an event-driven language, which makes it easy for many developers to use.

When answering, think about what role you’ve played in development and which of these benefits is most important to you.

Example: “JavaScript is an easy-to-learn, event-based language. It also doesn’t need a compiler to run the script, and it can run on its own without the server.”

What’s the difference between Java and JavaScript?

In very important ways, Java and JavaScript are not the same. Talk confidently about how the two languages are different to show that you know them both.

“Some of the most important ways in which Java and JavaScript are different are:

Java is a server-based programming language. At the time of compilation, variables must be set up and checked. Java program files are.

java, Java is standalone.

JavaScript has a more flexible syntax, doesn’t need to be compiled, is a scripting language, runs on the client side, and the program files end in.js. JavaScript needs a browser to work.

Why does a JS source file need a function block around the code?

This method is being used more and more in JS libraries that developers might use. If you know how to answer this question, it shows that you know about things that may only be done in libraries.

“This method puts the contents of a file in a private namespace. By using a namespace, JavaScript objects and the libraries they live in don’t get out of sync with each other.

What is NaN and what does it do?

If someone asks you to explain a word, it’s probably something you use every day. In this case, the term is “not a number,” which is written as “NaN.” This is something about values that JS developers need to know.

“If the value is not a number, the result of an operation is NaN.” This can happen in several different ways. For example, when an operation cannot be returned because part of a function was not a number or the value of the operation was not a number.

What kinds of information can JavaScript use?

This question tests how well you know JavaScript’s basics. To give the right answer, you need to quickly list all of the data formats that JavaScript can handle.

“In JavaScript, some types of data are:

  • Boolean information can either be true or false.
  • Number: A numeric value.
  • These are groups of related information that show what’s going on.
  • String: Values are stored in a string between the quotation marks.
  • These objects have been named, but they haven’t been set up yet.

Which, JavaScript or ASP, is faster, and why?

This question tests how well you know what JavaScript can do and what it can do for you. Give the correct answer, which is JavaScript, and explain why it is correct.

JavaScript is faster than ASP, which is one of its many benefits. It is faster and uses less resources because it is a client-side language that runs in the browser and doesn’t need a server. As a developer, I was asked by a client to make a web app that would run fast and not use a lot of resources.

I chose JavaScript to write the program because I was the only programmer on the project. I was able to finish the program, which the client wanted because he wanted a web app that loaded quickly. The client was able to keep people on their web app longer and keep them more interested because it worked so well.

Describe variables that haven’t been set or variables that haven’t been declared.

Programmers who use JavaScript will find variables that haven’t been declared or aren’t known what they are. Answer the question clearly and show that you know how to use the language to define variables that have not been declared or are not yet defined.

“Variables that haven’t been set up yet because they aren’t part of a program are called “undeclared.” If a program tries to run the variables before they are declared, it will log a runtime error. Undefined variables are ones that are declared but don’t have a value.

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