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Top Interview Questions to ask while hiring JavaScript Developers

  • Post published:July 6, 2020

Let us introduce you to the most fundamental and important javascript interview questions if you are looking to hire technical resources. The purpose of writing this article is to share valuable information with those, who are looking to hire remote JavaScript Developers or else looking for javascript jobs.

Why do you need to know about JavaScript interview questions?

The reason to choose this topic comes from the fact that JavaScript is one of the most popular programming languages and let’s be real, our developers and clients love building websites and apps with it. It currently dominates the market by offering the freedom to choose from a variety of libraries and frameworks within JavaScript software development services. As they say, “JavaScript is the programming language of the future.”

We see you, geeks! Would you wipe that grin off your face?

Break the “successful hiring code” with top javascript interview questions

As for those who are going to hire online JavaScript developers, they can take help from these questions before conducting a technical interview. Our extremely talented and expert javascript developers are always on the look for the latest libraries, new frameworks, and latest technology innovation.

Therefore, rest assure that you are getting your hands on these questions after extensive research and essential things that need to be included in javascript interview questions. This is also a new way for those who need to hire remote javascript developers. This sort of guideline enables you to self educate yourself about what you should expect from the potential developer.

In addition to this, this should serve as a guideline for the technical recruiters or those who intend to build a team of remote javascript developer or want to hire javascript developers. We will take some visual help from “the social network,” so you can avoid unpleasant events if you do your homework before the hiring.

Top javascript interview questions and answers to hire great developers

These javascript interview questions include the most fundamental of information and the most frequently asked questions. They allow you to judge the technical knowledge and expertise of the resource that you are going to hire. You can use these questions as a guide, and add more points from your side.

We are going to keep this short and sweet for you to understand. It is going to feel like a brisk morning walk. Once you go through these questions, you will be able to create an image of your desired javascript resource. This technical information will help you during the assessment and hiring.

This below list is of top javascript interview questions, that every developer should know and prepare for. You can expand your area of expertise and enhance skills with the latest JS trends in the market.

So let’s start with javascript interview questions one by one:

Question:1
What is the default behavior of JS (sync / async)?
Answer:
The default behavior of JS is synchronous
Question:2
Does JavaScript work by reference or by value?
Answer:
JavaScript works by reference for objects and arrays.
Question:3
What is hoisting?
Answer:
In JavaScript, there is a mechanism where variable and function declarations are moved to the top of their scopes before code execution. The below problem is also related to hoisting.
Question: 4
What values will be in logs? (This question is related to the above concept)
Answer:
var a = 10;

          console.log(a);     //10
          (function(){
             console.log(a);  // undefined
             var a = 9;
             console.log(a);  // 9
          });
          console.log(a);     // 10
Question: 5 What will be logged?
Answer:
console.log(NaN === NaN);   // false
console.log(NaN == NaN);    // false
Question: 6
How many data types are there in Javascript?
Answer:
There are 8 basic data types in JavaScript.
Question: 7
What will be the output?
Answer:
 console.log('start');      
          setTimeout(()=>{
                   console.log('mid') 
          }, 1000);
          console.log('end');

Answer:

Output:

 start

 end

 mid
Question:8
What is the use of keywork arguments in JS?
Answer:
Arguments can be used to get n no of arguments inside a function it is an array and we can loop through to get values.
function func1(a, b, c) {
  console.log(arguments[0]);
  // expected output: 1

  console.log(arguments[1]);
  // expected output: 2

  console.log(arguments[2]);
  // expected output: 3
}
Question:9
Reverse a JS string in minimal iterations or least complex algo.
Answer:
1- split to array
2- reverse array
3- join array using the array join method
4- String is reversed
Question:10
What will be the output?
Answer:
  for (var i = 0; i < 5; i++) {
                   setTimeout(()=> {
                             console.log(i);
                   }, i * 1000 );
          }.
Answer:

output:
5

5

5

5

5
Question:11
Will it print hi?
Answer:
It won’t go inside if as an empty string is considered false and won’t resolve inside if statement
var a = '';
          if(a){
                   alert('hi');
          }

Take your next step-hire javascript developer

Imagine you were driving towards a destination, but you’d be needing directions or a map, right? Similarly, when you know what you want to build. The next question arises. Build with home? Therefore, you can do research and hire the people who’d stand with you till completion of your journey.

Since you are already here. we would also like to tell that vteams has highly skilled javascript who turn ideas into super interactive websites and powerful apps.

So, if you are a technical recruiter looking to hire javascript developer. You can make the most from this interview questions list to find a great developer to help you with your next top website or app development.

But just in case, if at any point, you feel that you are stuck or it doesn’t make sense. (We understand its a lot to take when it comes to javascript). we at vteams would be happy to help you and walk you through this. You can always ping us at vteams.