Most important JavaScript interview questions: sure-fire for coding interviews in 2022
JS interview questions are coding interviews like any other interview can be stressful and intimidating. More so because of the multiple rounds that take place, it could easily feel like hell to go through.
If you have decided to make a career in programming and web development, here are the 2 things you should majorly focus on:
- Impressive work projects in your profile.
- Knowledge of JavaScript interview questions.
We have already discussed the important JavaScript resume projects in our previous blog. In this blog, I am going to highlight the important JS interview questions you should focus on and where to find them.
If you are aiming for java or C++ programming, SDE, or any other technical job profile, you can begin by preparing for these JavaScript interview questions that are common in most interviews. Also, we are also going to look at the resources you can utilize to prepare for your next technical interview.
Why JavaScript?
JavaScript is the language of choice for most professional programmers now because of its dynamic nature. It is an object-oriented language that has functional programming abilities. That’s why corporations are heavily searching for programmers that are well-versed in JavaScript. That’s why if you are aiming for a job as Software Developer you should keep an eye for these JS interview questions.
JavaScript interview questions are either basic, testing your general computer knowledge.
What is the constructor function in JavaScript?
Constructor functions are used to create objects in JavaScript with similar properties. The JavaScript constructor function is a normal function used to create multiple similar objects. JS constructor would help you in understanding a lot of JS coding interview questions. You can watch the following video to understand the constructor function and Object creation using the constructor function.
Constructor Functions in JavaScript
What is Recursion in JavaScript?
In recursion, a function calls itself multiple times to iterate over an operation. It makes the output easier. Understand the usage of Recursion in this video.
Introduction to Recursion — How Recursion Works | Print Decreasing using Recursion
What are callbacks?
A callback is a function that is used as an argument to other functions. You should also know how to write async code using callbacks.
Sync and Async programming with callbacks ft. event loop
Check out this video where you learn callbacks and how to write asynchronous code using callback functions.
In the process, we would also understand interrelated topics such as node APIs, callback queue, event loop, etc as well.
How to use Call(), apply(), and bind() methods?
These three methods are the prototype methods of the JavaScript built-in object Function. They allow us to call a function with a given ‘this’ context and arguments. Call apply bind in JavaScript is an important concept to answer JS interview questions.
This video introduces everything you need to know about call, apply and bind to tackle this question.
Call Apply and Bind |JavaScript interview series
What are Async and Await in JavaScript?
Async and Await in JavaScript are other crucial concepts in Web Development. Watch the following video to get a practical introduction to these concepts. Async is a function declared with the async keyword, and the await keyword is permitted within them.
Get to know these concepts in detail through this video:
Async Await Interview Questions
What is Functional Programming in Javascript?
Functional Programming in JavaScript is where we try to combine functions by applying and composing them. In this video, we discuss pure function in javaScript and other important JS interview questions. So, make sure to check them out!
Introduction to functional Programming ft Pure Functions
Explain “this” keyword
The ‘this’ keyword or ‘this’ variable is basically a special variable that is created for every execution context and therefore any function. It refers to the object that any function is a property of. This video is part of a series where we discuss object-oriented programming basics. Here we explain Object-oriented programming for beginners.
Learn ‘this’ Like Never before |JavaScript interview series
How are Higher-Order Functions in JavaScript?
Higher-order functions accept other functions, taking them as arguments or returning them.
They are an important concept that is quite common to be asked in interviews.
We introduce maps, filters, and reduce in this video on higher-order functions in javaScript.
Higher Order Functions (map , filter , reduce)| JavaScript Interview Series in Hindi
What are Closures in JavaScript?
Closures are created every time a function is created. It gives you access to outer function scope from inner functions. Closures in JavaScript is another important interview concept. This video would provide you with everything you need to know about js closure, which is important for many JS interview questions.
Closures in JavaScript | important interview concept
Explain Polyfills in JavaScript.
Polyfills in JavaScript is something that fills the gaps by implementing the features that you want the old browser to support natively. This video provides you with a good understanding of JS polyfills of Map, Filter, and Reduce. For more JS coding interview questions, check out our playlist.
Prototype and Polyfills of Map Filter and Reduce
What is Currying function in JavaScript?
With the rapid rise of functional programming in JavaScript, a lot of attention has been given to the curried function. So in this video, we will understand what they are, how they work, and how we can do function currying in JavaScript. It would help you in understanding a lot of JS coding interview questions.
Function currying with bind method ft Closures | Javascript interview series
What is Prototype and Prototypal Inheritance?
The prototypal inheritance is the most frequently asked topic during coding interviews, as the knowledge of prototype and prototypal inheritance tells how well you know JavaScript.
Prototype and Prototypal Inheritance
What is seTimeout() and setInterval()?
SetTimeout() is used to delay execution and setInterval() for repeating it. Watch this video to learn about these two methods using which we can schedule tasks in JavaScript. Stay with us to know more concepts to solve JS coding interview questions.
SetTimeout and SetInterval Ft. setInterval Polyfill
Explain JS Promise
A promise is a returned object to which we attach callbacks, instead of passing callbacks into a function. Depending on how the asynchronous operation completes, the promise state changes to either resolved or rejected. If you are a true JS developer, you must have used them a lot in your applications. Watch this video to understand the concept.
Read limited number of files with Promises parallelly and serially
This one is a common question in technical interviews. In the following video, you can learn to read limited files with Promises parallelly and serially using the file system module of Node.js. We would be using the fs promises keyword and a lot more important concepts that can help you solve many js coding interview questions.
Read Limited Files with Promises Parallely and serially
Read n number of files with Promises Parallelly and serially
Once you know how to read a limited number of files, you should go on to learn to read n number of files. Learn to read n number of files with Promises parallelly and serially using the file system module of Node.js through this video. We would be using the JS Promises keyword and a lot more important concepts that can help you solve many JS coding interview questions.
Read n number of files with Promises Parallely and serially
Null Vs Not Defined vs Undefined
In this video, we are discussing the not defined value, undefined value and null in Programming. Null is a value that we assign to a variable when we want to assign an empty value. But a lot of people don’t know the difference between null, defined & undefined. Javascript can be like that sometimes. This video clarifies the concept. Null Vs Undefined Vs not defined
Also, follow the rest of the series to know more sure-shot JS coding interview questions. Pepcoding offers free resources that you can use to prepare 700+ questions on DSA and Web Development and get placement in top-notch product-based companies. Contact us today to begin with your placement journey.
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