Skip to main content

javascript snippets interview questions set 1


javascript snippets interview questions set 1

Hey, I have just started a new set for javascript snippets interview questions which will make your understanding of javascript more clear.It's more like testing your knowledge and then clearing things that you have doubt or if you have heard for the first time about it.

So let's begin with testing and improving yourself,

Q1. Which operator returns true if the two compared values are not equal?





Q2. How is a forEach statement different from a for a statement?

 a)Only a for statement uses a callback function.

 b)A for statement is generic, but a forEach statement can be used only with an array.

 c)Only a forEach statement lets you specify your own iterator.

 d)A forEach statement is generic, but a for statement can be used only with an array.

Q3. Which statement creates a new object using the Person constructor?

 a)var student = new Person();

 b)var student = construct Person;

 c)var student = Person();

 d)var student = construct Person();

Q4. When would the final statement in the code shown be logged to the console?

let modal = document.querySelector('#result');



}, 10000);

console.log('Results shown');

 a)after 10 second

 b)after results are received from the HTTP request

 c)after 10000 seconds


Q5. You've written the code shown to log a set of consecutive values, but it instead results 

in the value 5, 5, 5, and 5 being logged to the console.

Which revised version of the code would result in the value 1, 2, 3 and 4 being logged?

 for (var i=1; i<=4; i++){



    }, i*10000);


a) for (var i=1; i<=4; i++){ (function(i){ setTimeout(function(){ console.log(j); }, j*1000); })(j) }

b) while (var i=1; i<=4; i++) { setTimeout(function() { console.log(i); }, i*1000); }

c) for (var i=1; i<=4; i++) { (function(j) { setTimeout(function(){ console.log(j); }, j*1000); })(i) }

d) for (var j=1; j<=4; j++) { setTimeout(function() { console.log(j); }, j*1000); }

Q6. What is the result in the console of running this code?

"use strict";

function logThis() {

    this.desc = "logger";



new logThis();

a) undefined

b) window

c) {desc: "logger"}

d) function

I hope you like the article. Please stay connected for more such articles.

Please check the comment sections for answers and if any doubts let me know there. 

You can also follow me on Twitter or Linkedin for the latest updates.

Written By:

Saurabh Joshi


  1. 1) Explanation:
    !== not equal value or not equal type
    var x = 5,
    x !== 5 false
    x !== "5"true
    x !== 8 true

  2. 6)Explanation:
    When you call a function with new keyword,
    JavaScript creates a new empty object. If ‘this’ keyword is used within that function, it refers to the newly created empty object.
    If you’re not explicitly returning any object,
    JavaScript would return that newly created object/

  3. I think Q5.c has typo. it should be ( , instead of { before fitst function for IIFE


Post a Comment

Popular posts from this blog

Node JS:Understanding bin in package.json.

Well as a Node Js developer we know package.json as dependency file where we keep a note of all dependencies of our project. Here we will be looking at what is bin in package.json? To understand this we first need to understand command line application and it's purpose. CLI applications are mostly used to automate things such as deployments of application,running tests,building reports and the list goes on and on. So lets start with creating our first CLI application. First, let’s make sure you have the tools required. To complete this tutorial, you will need the following: 1)A recent version of Node.js downloaded and installed 2)A good text editor, such as Visual Studio Code Next, open your computer’s command prompt (Windows) or terminal (macOS/Linux). Change the current directory to the folder where you save your documents or projects. Enter the following commands to create a new project folder and initialize the project. mkdir hello-cli cd hello-cli npm init Nex

Node.js: Extract text from image using Tesseract.

In this article, we will see how to extract text from images using Tesseract . So let's start with this use-case, Suppose you have 300 screenshot images in your mobile which has an email attribute that you need for some reason like growing your network or for email marketing. To get an email from all these images manually into CSV or excel will take a lot of time. So now we will check how to automate this thing. First, you need to install Tesseract OCR( An optical character recognition engine ) pre-built binary package for a particular OS. I have tested it for Windows 10. For Windows 10, you can install  it from here. For other OS you make check  this link. So once you install Tesseract from windows setup, you also need to set path variable probably, 'C:\Program Files\Tesseract-OCR' to access it from any location. Then you need to install textract library from npm. To read the path of these 300 images we can select all images and can rename it to som

Node.js: Bundling your Node.js application to single executable for Windows.

In this article, we will see how to bundle Node.js application to a single executable for Windows. What's the need? Well recently, I had taken a work where I needed to convert pdf's(Of similar format) to excel sheet. So I was reading the pdf's from a folder in desktop and I was storing the output excel sheet into a separate folder on the desktop. I used Node.js for the program. Now the client wanted it to install the program on 25 windows machine and his budget was really low. So it was also not possible for me to install node.js for 25 machines and then install the required dependency for each one. One of the solution: While I was searching for an easy solution I found this amazing npm module pkg . This module can make your node.js app work like plug and play type. No need to install Node.js on the client machine or any other dependency.  It helps to make a commercial or trial version of your node.js application without exposing the source code. I found