Top 100 JavaScript Interview Questions and Answers 2023

Let’s see a simple code to create an array using object literal. The history object of a browser can be used to switch to history pages such as back and forward from the current page or another page. The window object is created automatically by the browser that represents a window of a browser. It can be used to access and change the content of HTML. Top tips and best samples for creating a Django developer CV.

The negative infinity in JavaScript is a constant value that is used to represent the lowest available value. It means that no other number is lesser than this value. It can be generated using a self-made function or by an arithmetic operation. JavaScript shows the NEGATIVE_INFINITY value as -Infinity. Write a function to implement breadth-first search in a binary tree in JavaScript. Write a function to implement a linked list in JavaScript.

What will be the result of 3 + 2 + “7”?

JavaJavaScriptJava is a complete and strongly typed programming language used for backend coding. Common JavaScript interview questions may include basic syntax, structure, and programming concepts such as scope and event handling. Other potential topics for discussion might include data types, object-oriented design patterns, or performance optimization strategies. Undeclared variables are created when you assign a value to an identifier that is not previously created using var, let or const. Undeclared variables will be defined globally, outside of the current scope.

You can differentiate between Inline Functions and Anonymous since an inline function is assigned to a variable and can be easily reused. This is the difference between an internal script and an external script. The JavaScript this keyword refers to the object it belongs to. This has different values depending on where it is used. In a method, this refers to the owner object and in a function, this refers to the global object.

Node JS: Discover 10+ Courses For Learning To Code With Node JS

It can be used to avoid polluting the global namespace since the variables created inside the IIFE are only visible inside its scope. React is a JavaScript framework that simplifies the process of creating interactive UIs. Its hot reload feature allows developers to immediately see changes as they’re made. It’s part of React Native, which is used to create mobile applications. React’s one-way data flow is more intuitive than two-way data binding.

• The function then uses the Array.from() method to convert the set back into an array, which it returns as the final result.
• JavaScript adds interaction to otherwise static web pages and makes them react to users’ inputs.
• The document is loaded inside the window and is a property of the window.
• Variable typing allows you to assign a numerical value to a variable.

All objects that emit events are instances of the EventEmitter class. These objects expose an eventEmitter.on() function that allows one or more functions to be attached to named events emitted by the object. Functional programming produces programs by composing mathematical functions and avoids shared state & mutable data.

What are the different types of NoSQL databases?

No matter how well a candidate answers questions about JavaScript, you’ll ultimately want to see them put their knowledge into action by doing some actual coding. Here are some coding challenges you can use to gauge how an applicant handles coding problems. If you don’t want to change the original array, use the .map() loop. If you just need to iterate over an existing array, use the forEach loop. A generator lets you choose to jump out of a function and lets the outer code determine when to jump back in. It also lets you control asynchronous call outside of your code.

Location.replace- In this, we can’t get access back the actual document. Location.href- This is one of the ways to redirect hire javaScript developer a page. Array splice() method removes the items of the selected array from the array and does not form another array.

What is the difference between “null” and “undefined” in JavaScript?

So, if you’re looking for help with JavaScript interviews, you’re in the right place. We’ve compiled a list of the 60 top JavaScript interview questions and answers, ranging from beginner to advanced. So buckle in, and use this article or the PDF download as a confidence-building resource to prepare for your next JavaScript interview.

JavaScript remains a firm favorite among aspiring software developers and seasoned pros, as shown by its number 1 ranking in the annual Stack Overflow Developer Survey. NULL is used to represent the absence of a value or object. It implies neither an https://globalcloudteam.com/ object, nor a null string, nor a valid boolean, nor a number, nor an array object. There are two ways to read and write a file using JavaScript. The setTimeout function is used to start a timer that calls a specific function after a specified delay.

How can you convert the string of any base to an integer in JavaScript?

Refer to these questions and answers to crack an interview in the very first attempt. The answer is Emma Woodhouse and John Smith because the context of a function depends on how it’s invoked, not how it’s defined. In this example, the function returns the property “full name” of “window.” The result of this code will be undefined and 5 because variables don’t retain any assigned value when they’re hoisted.